courtesy: Flickr

I was asked this question in a recent conversation – how high should a home weather station be placed?

There’s no such thing as a stupid question, but there is such a thing as a question that starts from bad assumptions.

The key here is to realise that there are two types of weather station.

1. All-in-one weather station – combines sensors and digital display in one unit.
2. Base station with remote sensors for gathering weather data.

On this site we try to steer people away from the all-in-one units as these tend to be cheap, inaccurate units. Because they are all-in-one, they can only monitor weather from where you position them.

They are only designed to be used indoors (we exclude specialist handheld professional gear). This means that while they can get a fair fix on changes in atmospheric pressure, they have zero chance of monitoring for external humidity, temperature or wind conditions.

For such devices, it doesn’t matter where you place them – they won’t get any better.

We do understand that some people see these as a way to get into home weather monitoring – we just ask that you do not spend too much on one of these because we are sure you will want to upgrade within weeks or even days of using one.

For a base station with remote sensors, the trick is to place each sensor in the location that leads to optimal data for whichever element of the weather that sensor is reading.

So for an anemometer you want full exposure to the wind. Position the anemometer as high as you can (to avoid turbulence from buildings) but make sure you can easily access the anemometer because you will have to replace the batteries every few months.

Other sensors work well on ground level (rain gauge) or at shoulder height (e.g. external hygrometer) so you can read the sensor’s own digital read-out.

So Where Should The Home Weather Station Be Placed?

See here for more on how to find the best general weather station locations.

The home weather station itself should be snugly warm and dry inside your house either table-top or wall-mounted for ease-of use.

How High Should a Home Weather Station be Placed? is a post from: Weather Stations For Home

Recently the reduction of costs and advances in wireless technology has meant that many private homes and schools have been in a position to acquire a weather monitoring station.

These systems have much to offer schools across many different departments. The purpose of this short article is to highlight the possible benefits for schools considering acquiring a weather monitoring station of their own.

What is in a Typical School Weather Station?

The equipment will typically consists of the following (the example shown here is the Oregon Scientific WMR88):

A central weather station display unit:

A typical central display unit for a school weather station

Most displays will include a built-in barometric pressure sensor.

A suite of wireless sensors. These require no cabling, each sensor works on its own radio channel frequency and is battery powered. The range from sensor to the receiver in the central weather station display is typically of the order of 100m/300Ft.

A set of wireless weather sensors for a school weather station

The usual sensors included will be:

-A combined wind speed and direction sensor.

-Tipping bucket rain gauge.

-Combined air temperature and humidity sensor.

Each are lightweight and require nothing additional in terms of installation hardware beyond the mounting brackets and assemblies supplied (although most do not supply a Stevenson Screen for the combined air temperature and humidity sensor and while you certainly can use the sensor as supplied it is preferable to acquire a small screen for the sake of measurement accuracy).  For more suggestions regarding suitable installation locations try here.

A USB connection at the weather station display for connection to a PC or Mac to allow the download of the data collected. Most weather station suppliers either provide a DVD with the software required or you can download it from the manufacturer’s website.

What Could a Weather Station Offer the School?

The value of having the school’s own weather system when teaching natural sciences is of course obvious and needs no further elucidation here.

A weather station presented online can be used to elevate the visibility of the school within the local community. Combining real time current and historical local weather data along with (for example) a live web cam can transform your school’s website from something visited once or twice a term into part of parents’ daily online routine.

Where a school newspaper is in circulation what could be more relevant than the local weather forecast from the school’s own weather station and forecasters?

As part of web site development teaching, the challenge of acquiring the collected data and presenting it in a lucid and attractive way is an excellent way of engaging the enthusiasm of pupils.

The mathematical handling of the instantaneous real time data collected from the weather station can used as a tangible application for all sorts of statistical analysis techniques from simple means through to standard deviation. Similarly the derivation of weather parameters such as dew point can be used with real world examples when teaching logarithms and natural exponents.

What Have Other Schools Done with a Weather Station?

As an illustration of what can be done here are some examples of schools that have used a weather station of their own to develop a hugely impressive online presence.

Bablake School in Coventry have had a weather station since 1977 and have developed a wonderful web site around it which is well worth a visit , with a daily weather forecast for the Coventry area as well as comments on current weather trends, it is easy to imagine that many local people will use this as their weather information source as well as being a wonderful promotional tool for the school itself.  Somewhere behind the scenes must be a pretty keen maths teacher too because they have an exhaustive set of analysis of the historical weather data gathered from the station.

The Maiden Erlegh School in Wokingham has a simple but very effective weather display updated every minute or so combined with a webcam :

The Maiden Erlegh Weather Station Web Display.

The teacher responsible for organising the weather station (and what sounds like a very successful weather club) at the Maiden Erlegh School outlines the advantages that he feels having a weather station have brought in an article on the Geographical Association website .

The price for such a weather station is in the region of £150. A school weather station offers a myriad of potential benefits that are limited only by the collective imagination of the school community, that must be a bargain for the price.

Weather Stations for Schools is a post from: Weather Stations For Home

What is Relative Humidity?

Relative humidity is a measure of the amount of moisture (held invisibly as water vapour) that a volume of air is presently holding relative to the full amount that it is capable of holding. When a volume of air holds as much water vapour as it can (that is to say it is “saturated”) then it has a relative humidity of 100%. When it holds only half of this amount then the relative humidity (often abbreviated to RH) is 50%.

When the air holds as much water vapour as it can, additional water can no longer exist as vapour but as droplets or condensation

The warmer the air, the greater the amount of moisture that the air can hold as vapour. It follows therefore that on a day when the temperature is 20 degrees Celsius a 100% humidity figure will represent a lower amount of moisture in the air than will be present for a 100%RH figure on a day where the temperature is 30 degrees Celsius.  This also implies therefore that if the temperature increases then the relative humidity will decrease (as the amount of moisture that represents 100% will increase with the temperature). This of course assumes no change to the absolute humidity (the amount of moisture in the air in terms of grams of water per Kg of air)

It is worth noting that in reality the water is not in any sense dissolved in the air. The water vapour exists within the gases that make up the air but are not dissolved in them.

How is Relative Humidity Measured?

Relative humidity is most commonly measured either manually using a whirling hygrometer or automatically using either automated wet and dry air temperature sensors or using an electronic humidity sensor.

A whirling hygrometer made by R.W. Munro. This measures wet and dry air temperature.

Wet and dry air temperature sensors are exactly what their names imply. The dry air temperature sensor is the one used to report air temperature for any standard weather report. The wet air temperature has a thin gauze wick wrapped over the temperature sensing element. The temperature sensor (with one end of the wick wrapped around it) is exposed in the air but the other end of the wick runs down into a bottle of distilled water. This draws water up from the reservoir of distilled water, it then evaporates from the surface of the air temperature sensor and causes a drop in the measured temperature (due to the heat lost in evaporating the water from the wick).

A set of dry and wet air temperature sensors from Munro Instruments. The wet air sensor is on the right hand side (the wick descending into the bottle of water can be clearly seen).

Unless the relative humidity is at 100% the wet air temperature sensor will read less than the dry air temperature sensor because of the evaporative cooling of the water in the wick.  If the RH=100% then the water in the wick cannot evaporate (as the air around it can hold no more water vapour) and the wet air temperature = dry air temperature. The difference between the wet and dry can be used to calculate (or look up in a table) the humidity.

Most electronic sensors work by measuring the capacitance of a volume of air, the capacitance will vary with the amount of moisture in the air.

An Oregon Scientific wireless relative humidity sensor for the home.

Why is Relative Humidity of Interest?

To us as humans relative humidity has a lot to do with how hot or cold we feel. The human body naturally cools by the evaporation of moisture from the surface of the skin. Heat from our bodies is used to evaporated this moisture and through this loss of generated heat we feel cooler.

When the air is more humid the rate of evaporation is slowed and so we feel warmer. Conversely if the humidity is low then the rate of evaporation is faster and the cooling effect that much more efficient. This is why people often talk about a dry heat being more bearable than a humid one, because it is easier to cool in low humidity conditions.

The relationship between the amount of water vapour in air and the air temperature is not a linear one, at cooler air temperatures the amount of water vapour that can be held increases relatively slowly but at higher temperatures the rate of increase is far higher. For example, in very rounded figures, at 5 degrees Celsius, 100% RH represents around 5g of water per Kg of air) at 10 degrees this is around 9g. At  40 degrees Celsius the water amount is around 50g per Kg of air but at 45 degrees Celsius it is around  70g. This is why in tropical areas the high heat and humidity can feel so oppressive when people are not accustomed to it.

When the RH reaches 100% then the air can carry no more water vapour and any excess moisture now forms water droplets resulting in condensation. Condensation can ruin some essential work operations such as industrial painting and the laying of road surfaces. For these and many other activities it is important to monitor the relative humidity and the dew point in order to choose a suitable time for the activity such that condensation can be avoided.

How Can You Measure Relative Humidity at Home?

There are now many inexpensive weather stations available for the home which can measure relative humidity or a simple whirling hygrometer will do the job easily and well.

The Dummies Guide to Relative Humidity is a post from: Weather Stations For Home

If you are interested in getting even more from your home weather station then have you considered dew point? If your station measures humidity and air temperature then you already have all that you need.

What is Dew Point Temperature?

Water droplets condensing out of the air as it cools

The dew point is the temperature at which moisture in the air will condense out into water droplets.

Moisture in the air is of course invisible but when the dew point temperature is reached and the moisture forms water droplets, a mist or fog will form.

The warmer the air the more moisture the air can hold without it condensing out.

This is why you can see your breath on a cold day but not on a warm one.

On a cold day you breathe out warm air which holds lots of moisture, it then hits the cold air and is immediately chilled, this reduces the amount of moisture that can be held and the rest condenses out in a cloud of water droplets.

The dew point is the temperature at which moisture in the air changes to water droplets.

What Use is Dew Point?

Dew point and humidity are closely linked (barometric pressure has some influence on both). The closer the actual air temperature is to the dew point temperature the more moist the air and therefore the greater the humidity.

At 100% humidity the air is saturated with water, that is to say the air cannot hold any more moisture, this happens when the air temperature is equal to the dew point. Below the dew point all the moisture that cannot be held by the air condenses out as water droplets.

This also explains why high humidity in the tropics is so uncomfortable, the high temperature causes the body to sweat, usually the heat from the body would be used to evaporate that sweat causing cooling of that body, but in these conditions the sweat cannot evaporate because the air is already saturated with moisture so no cooling occurs, just more sweat and more heat.

Away from the tropics the air is generally colder; therefore the dew point is lower meaning that the saturation point is reached at a much colder temperature.

When therefore, the air is warm enough for the human body to sweat the air holds a relatively small amount of moisture and so evaporation of the sweat and consequent cooling are not a problem.

The Most Important Application for Dew Point

Perhaps the most important application for dew point is aviation.

It is useful in predicting where and when visibility problems associated with fog and mist might arise as well as predicting where and at what altitudes problems such as icing might occur.

pic: erik.altitude under CC BY-ND

aircraft icing

.

How Is Dew Point Measured and Calculated?

Most commonly, dew point is derived from measurements of air temperature and relative humidity.

The calculation for dew point from these values is a little fearsome to say the least (see below)

But much more commonly a dew point table is used (an example is shown below):

Cross reference the air temperature with humidity to find the dew point

In the example above an air temperature of 30 degrees Celsius and relative humidity of 70% means a dew point of 23.9 degrees Celsius.

The calculation is a little more complicated:

Dew Point (Calculated from dry air temperature and relative humidity):

Dew Point (°C) = (239x)/(17.38-x)

Where:

x = ln(Vp/6.107)

and

Vp = RH/100 (6.107 exp(17.38Td/(239.0+Td)))  for Td (dry air temperature) > or = 0

Vp = RH/100 (6.107 exp(22.44Td/(272.4+Td)))  for Td < 0.

Ln= natural log and Vp= vapour pressure).

As you can see, unless you are a glutton for mathematical punishment the easiest way to find the dew point is to take the readings of air temperature and relative humidity from your home weather station and use a dew point lookup table.

Dew Point, What is it and What is it Used for? is a post from: Weather Stations For Home

Whether your interest extends from owning a home weather station, you are thinking about installing a wind generator turbine or you just have some unanswered questions, hopefully you will find some interesting information within this dummies guide to wind measurement.

We will show how wind speed and wind direction are measured and reported.

Let’s start with the basics:

What is Wind and Why Do We Have it?

Wind is simply the movement of air from one location to another. It is driven by pressure differences. Watch any weather forecast and you will be shown a chart that describes the location of pressure systems each of which is described as either low or high.

Weather chart, the lines superimposed (isobars) link all areas of equal pressure (similar to a contour map)

As you would expect air will move from an area of high pressure to one of low pressure. This would of course continue until (theoretically at least) a state of equilibrium was reached around the globe consisting of a single universal pressure all over the world and no more air movement.

What causes the pressure differences in the first place is an excellent question but beyond the scope of this article (fundamentally it is caused by heat differences around the globe).

As we have seen from the weather channel’s synoptic charts these pressure systems are large, broadly circular volumes of air.

You would probably expect that the air would rush from a high pressure area directly into a low pressure area in a nice straight line (it would certainly make it easy to work out the wind direction from a pressure chart). In reality though it is a little more complicated than that.

Why? Because the earth is rotating.

It is the result of a phenomenon known as the Coriolis Effect.

To explain it in an extremely simplistic way, a movement in a straight line appears to move in a curved line when seen from a rotating reference point. Imagine a toy globe.

Now imagine taking a penlight and describing a straight line on the surface of the globe with the illuminated dot from the North Pole down through Canada and the USA then straight down to the equator.

Do it again, with the torch in the same position and describing the same line but this time slowly rotate the globe as you do it. This time of course the line will follow a very different path of the face of the globe. If you were watching this giant penlight in the sky from the rotating surface of the globe it would describe a curve as you physically moved away from it. This is (at least in part) why winds appear to spiral around pressure systems from our earth-bound perspective.

The red arrow shows the path of the penlight as viewed from the ground

If you are in the northern hemisphere wind will rotate in an anticlockwise direction around a low pressure area.

Conversely wind will move in a clockwise direction around a high pressure system (they are opposite to each other as the wind is moving in to a low pressure system but out of a high pressure system).

If you are in the southern hemisphere these directions are reversed. This is because the apparent motion of a straight line is reversed below the equator.

If you go back to the imaginary globe, this time take the penlight in a straight line from the south pole to the equator.

Think about the direction that the penlight would appear to take to an observer on the globe surface in the southern hemisphere.

Once you get the hang of it it’s easy to get a feel for wind speed and direction from a weather chart:

The greater the difference in pressure between the high and low pressure areas the greater the wind speed.

This difference is indicated by the spacing of the isobar lines on a weather chart. An isobar is a line drawn on weather map linking all areas of equal pressure. Isobars will be plotted in fixed steps (for example an isobar drawn linking areas in which the pressure is 990mB, the next one for 994mB, the next one 998mB etc).

Therefore if the isobars are plotted very close together on a map then the pressure is changing quickly over a short geographical area and wind will be strong.

Conversely if the isobars are further apart the pressure difference over the same area is less and the wind will be weaker.

It can be seen now how a weather chart with isobars will tell you much about the wind speed and direction. The spacing of the isobars will dictate the speed of the wind and the position of the high and low pressure areas the direction.

How is Wind Measurement Reported?

The answer to this depends very much upon the application. For example climatologists studying long term trends in weather will have very different requirements from pilots making a final runway approach at an airport.

How would you report something as variable as wind speed?

You can of course measure the speed of air movement at any given moment in time, but that is just  a snap shot and may not even be representative, you may have taken the measurement in a momentary lull.

OK so you can average it, but over how long? A second, a minute, an hour, a week?

You could pretty much get any average wind speed figure imaginable by choosing  the period over which you average.

The point that I am making is that how the data is processed is at least as important as how it is measured. The way in which it will be processed will depend upon who needs the information and what they need it for.

The example earlier of the airline pilot is a good illustration:

Typically when flying en-route between airports and reviewing the weather ahead pilots will use 10 minute mean wind speed (that is to say all the individual measurements taken over the previous 10 minutes have been averaged).

10 minute mean data gives a good general idea of wind conditions and trends in the wind speeds (whether it is rising or falling for example).

When they are on final approach to an airport they will change to using 2 minute mean wind data. Why?

Because it will give a more immediate indication of what the wind is doing right now. Imagine a sudden step change in the wind speed, if you are reporting a 10 minute mean then it will take a while for the scale of that step change to become clear.

On the other hand a 2 minute mean will react much more quickly to that step change. This is important of course to a pilot who needs to know immediately if the wind changes significantly.

This might lead you to think – why average the reading at all? Just report it as soon as it has been measured. This takes us back to the intrinsically variable nature of the wind. A single measurement may not be representative, so in averaging it we are attempting better to represent it but at the potential cost of a slower reaction to a change in that wind.

Another key characteristic of wind speed which has not yet been addressed is its gusty nature. We have all experienced being out walking in steady breeze but being buffeted occasionally by strong gusts.

How can this be reported?

Going back to pilots again this is key information for them, they not only need to know the mean wind speed but also the gust. To do this someone needs to define what constitutes a gust. In the U.K. this is the Meteorological Office.

A gust is defined as any measured wind speed that exceeds the average wind speed by at least 10 Knots (1 knot = 1.15 miles per hour). A gust is always therefore associated with an average wind speed.

For example a 10 minute gust figure will be the highest measured wind speed in the last 10 minutes that exceeds the 10 minute average speed by at least 10 knots.

The wind speed may therefore be reported as “26 knots gusting 39″  (meaning that the mean wind speed is 26 knots but a maximum measurement of 39 knots was recorded). If that maximum had been 35 knots then no gust would have been reported as the maximum was not at least 10 knots higher than the mean.

Between the reported average and gust figures you can see how it is possible to convey a lot about the strength and behaviour of a wind.

Wind direction is usually reported in degrees :

Cardinal points (north, east, south and west) and their corresponding value in degrees- note that in meteorology the 000 degrees value is only used when there is no wind to report, a wind straight out of the north would be reported as 360 degrees

The direction states where the wind is moving from (an easterly is a movement of air from the east heading to the west). It is worth noting that the direction is usually reported in terms of either ‘magnetic’ or ‘true’.

This refers to whether the north used as the reference is magnetic north or true north. The former moves both over time and with respect to where on the globe you are located.

The difference between the two can be significant (again depending upon where you are). The latter does not vary with time or location.

Wind is usually reported to the nearest 10 degrees (for example if the measured wind direction was 272 degrees it would be reported as 270 degrees and similarly if the measured direction was 186 it would be reported as 190 degrees).

All wind measurement equipment (on shore or on fixed installations offshore) should be aligned to true north.

The same considerations about the processing of wind speed measurements also apply to wind direction.

Typically a 2 or 10 minute mean wind speed will be reported in association with the corresponding 2 or 10 minute mean wind direction. Unless otherwise stated it should be assumed that any wind direction reported is relative to true north.

Wind direction will often include an arc of measurements, for example a mean wind direction may be reported along with the minimum and maximum direction recorded over the mean interval.

This is certainly the case for reporting weather in aviation applications and again is an attempt succinctly to convey the behaviour of the wind.

How Do You Measure Wind Speed and Wind Direction?

At the simplest level with a wind sock. To the skilled eye this can convey pretty much everything that you need to know for a particular application and of course in terms of cost and maintenance requirements it is hard to beat.

A wind sock with aviation colour markings

For immediacy, conveying the wind conditions at a pinpoint location and with doing so with high visibility there is nothing else to beat it.

This is why despite the wide range of  far more sophisticated equipment installed at any airport, you will also see a wind sock or two around.

An anemometer is the name given to an instrument that measures wind speed, they vary in their design and method of measurement.

Rotating Wind Speed and Direction Sensors:

The most common is still the widely recognised spinning cup variety. A set of cups attached to a rotating shaft are oriented to be propelled by the wind. The cups, driven by the wind cause the shaft to rotate at a rate proportional to the wind speed.

The classic RW Munro IM124 generator type anemometer, found all over the world

Different types of spinning cup anemometer use different methods to determine the rate of rotation (and hence the wind speed).

The most widely used is probably the dynamo (or generator) type.

Permanent magnets are mounted on the rotating shaft. The shaft rotates within a chassis lined with electrical windings.

As any senior school physics student will tell you, if you move a magnet next to an electrical winding you will generate an electrical signal.

The magnitude (and also the frequency) of the electrical signal generated by the shaft-mounted magnets spinning is directly proportional to the wind speed.

The beauty of this type of wind speed measurement is that it requires no power at the sensor, the signal is generated by the instrument itself.

Typically the spinning cup anemometer would be connected to a wind speed dial display:

A selection of RW Munro wind speed dials, the dial is powered entirely by the anemometer

Often it will also be connected to a chart recorder (a paper chart on which a pen records the wind speed), this maintains a record of the wind speed over time rather than the simple snapshot offered by the wind dial display.

An RW Munro wind speed chart recorder

These days of course it is very likely that the signal from the anemometer will be taken to a computer at some point, however the dynamo type of sensor does not lend itself to computer logging as its output signal requires considerable modification before it can be acquired by digital equipment.

The dynamo type is essentially a low-tech creation and has therefore found favour all over the world for its low cost and ease of maintenance and repair.

Another common variant of the spinning cup type of anemometer is the optical encoder disk type.

The sensor uses the same cups-mounted-on-a-spinning-shaft arrangement but instead of having permanent magnets mounted on the shaft there is a thin disk. The wind spins the cups which in turn spins the encoder disk.

Mounted in fixed positions on either side of the disk are an infra-red transmitter diode (on one side of the disk) and directly above it but on the opposite side of the encoder disk an infra red receiver diode.

The receiver diode switches on whenever it receives a signal from the transmitter. The hole in the encoder disk is located such that it will pass between the diodes once per revolution of the shaft.

By monitoring the switch rate of the receiver diode the detecting equipment can calculate the speed at which the shaft is rotating and therefore the wind speed.

There are many other ways of converting the rotation of anemometer cups into a measurable wind speed but all operate along the same lines.

The wind turns the cups, the cups are fixed to a rotating shaft so the shaft rotates, the speed of shaft rotation is measured and the wind speed then deduced.

The classic handheld wind speed anemometer

As you might imagine wind speed sensors come in all shapes and sizes as well as being made from a wide range of materials from heavy brass to lightweight plastic.

This variation necessarily gives rise to a range of responses to the same wind conditions. Different sensors will be quicker or slower to respond to changes in air flow. This gives rise a range of defining characteristics used in conjunction with each senor. An example is the distance constant.

Imagine how different anemometers will respond to a sudden increase in wind speed, a light plastic instrument will reach the new speed almost instantly but a larger brass sensor will take much longer.

The distance constant is used to define this difference in response time. If you consider the wind as a column of air that moves through the anemometer then, broadly speaking, the distance constant for any given sensor is the length of column of air that will have to pass through the sensor before it will reach the true wind speed rotation rate.

A fast response plastic sensor will have a short distance constant and conversely a heavier, slower response sensor will have a longer distance constant.

While there are statistical methods which can even out some of the differences between the data measured by wind speed sensors with very different distance constants, it is generally the case that weather monitoring organisations try to stick to using sensors with broadly comparable characteristics  for their official measurements.

When using a spinning cup anemometer you also need a way of measuring wind direction. This is almost universally done using a direction vane.

Just as you might see on a church roof, the wind direction sensor utilises a vane which will rotate to align itself into the wind.

The vane is fixed to a rotating shaft and so the movement of the vane is transmitted to the movement of the shaft which typically will move the wiper on a circular potentiometer (a variable resistor).

This results in a signal voltage which directly corresponds to the physical position of the wind vane.

A combined wind speed (top section) and direction sensor, the IM146 from RW Munro.

Non-Rotating Wind Measurement Instrumentation:

In the past the requirement for wind speed sensors that do not use spinning cups or similar designs had been limited to a few applications where such designs were not practicable, notably in regions with extremely low temperatures which would cause moving parts to ice-up or in remote locations where access was difficult and / or expensive.

Instruments with moving parts inevitably require significant maintenance due to the physical strain (on bearings for example) of running 24 hours per day.

However such equipment is now becoming more widely used partly because of the reduced maintenance implications and in some instances because it can perform measurements that are not possible with the spinning cup type of sensor.

Ultrasonic Anemometer:

This sensor has no moving parts at all. It consists of an array of ultrasonic emitter and receivers.

The basic principle involved is that the instrument measures the time taken for an ultrasonic pulse to pass from an emitter to a receiver. It will then reverse the direction and measure the time taken for a pulse travelling in the opposite direction.

If there was no wind then the time taken in each direction would be identical. The difference in the measured times taken between directions is a function of the air flow rate (wind speed) in between the emitters and receivers.

There are usually 2 sets of transceivers (combined ultrasound transmitters and receivers), one pair pointed along the north – south axis and the other along the east – west. The results can then be vectored to produce a wind speed and direction.

An ultrasonic wind sensor made by Gill instruments. Each of the 4 heads is a combined ultrasound emitter and receiver

In reality the air temperature will also have an influence on ultrasound propagation time and so the sensor will factor this in.

Wind Profilers:

Profilers are devices used to measure wind speed and directions at various elevations from ground level up to high altitudes  (even  as high as 15Km above sea level depending upon the type of instrument) and hence produce a wind “profile” up through the atmosphere.

Profilers are typically weather radar.

This is usually Doppler radar.  By tracking the shift in frequency between emitted radar pulses and their reflected signals received back at the radar it is possible to deduce the speed and direction of air movement. The radar waves are reflected off tiny airborne particles.

There are also devices which use sound wave pulses to achieve the same ends (although their range is much less than a weather radar’s).

Needless to say the cost of wind profiling equipment is several orders of magnitude greater than any other method.

Hopefully you have found this brief and admittedly very basic guide to wind measurement interesting.

If so then I can heartily recommend getting a home weather station, they are an inexpensive and endlessly fascinating addition to a home and these days the external sensors (including the wind measurement instruments of course) tend to be wireless and so the installation is easy.

Wind Measurement for Dummies is a post from: Weather Stations For Home

One of the more expensive costs associated with adding a wind turbine to your home is the installation of the home wind turbine itself. It is therefore vital that you get its placement right first time. The cost implications of having to relocate it are going to impact heavily on the savings that you are expecting to gain from the project.

How Do the Experts Choose Where to Place a Wind Turbine?

The professionals when choosing the individual locations for each turbine on a wind farm spend huge sums on establishing whether or not a particular spot is optimal by creating wind maps over an extended period covering the entire area of the farm.

They do this by locating multiple anemometers (wind speed measurement devices) at various spots and various elevations around the wind farm location. The larger wind farm projects will use wind profile devices which can measure wind speeds simultaneously at multiple heights.

A typical wind profiler (a little on the large side for your back garden)

The data from each sensor is logged over a period of months. The sensors are then moved to other locations and the logging repeated. This process is repeated until the ideal placement and elevations for wind energy generation have been established.

Does this Matter for My Small Wind Generator?

Absolutely it does. You are looking to gain a long-term return from your generator in terms of reduced fuel bills over the coming years, over that sort of time scale the smallest change in average wind speed at one site over another will be significant.

What help is Available for the Home Wind Energy Turbine User?

You will doubtless have a number of possible sites and elevations in mind for the location of your generator but you need to choose the best spot and then the best height above that spot. You of course start with your prevailing wind direction, in the UK generally the prevailing wind direction is a south westerly but a further investigation of the Meteorlogical Office resources online is a good starting place . For example the wind data reported for here for the West of Scotland. Remember of course that wind direction reports the direction from which the wind is coming.

This is only the first step, the local effect on wind of landforms and structures (even distant ones) is something that is impossible to calculate it can only be discovered by trial and error. But when it comes to installing your wind turbine you want to get it right first time.

Ideally what you need is a means of measuring the wind speed without spending a great deal of money. This will pay dividends over the long term and also save the costly business of potentially relocating the turbine.

The cost of home weather stations has dropped over the years, they will provide a small easily mountable wind speed and direction sensor which connects to a central weather station display unit to give wind speed and direction displays.

Here are some of the characteristics to look for in a weather station for your home that will be ideal for the purposes of identifying the optimum location and elevation for your home wind energy generator:

1. The wind speed and direction sensor should be wireless (all you have to do is mount the small and light sensor on a temporary pole, no hassle of running cables) and the sensor will communicate via a radio link with the central display.
2. The display station should have the facility to download the recorded data to a computer (usually via a USB port). This will then allow you to analyse the data. Most home weather station manufacturers supply easy to use software to analyse the collected wind data.

The station that I used for the job was the Oregon WMR88.

The sensors supplied as standard with the WMR88 home weather station

It was not expensive and fulfilled the requirements listed above. Having said that there are plenty of others with similar specifications at around the same price.

I had three possible sites in mind and put the wind speed and direction sensor at each for a couple of weeks on a light plastic pole (which I simply tied with rope and tie-wraps to various local structures) . The sensor weighed a little over 100g and so was easy to place almost anywhere. Of course the longer that you can leave the sensor at each site the more representative of the overall exposure the data logged will be.

In the end this testing firmly demonstrated that one of my possible sites was not reliable, there was not much to choose between the other two.

Why Use a Home Wind Speed and Direction Sensor to Choose Your Home Wind Turbine Location?

A site that looks open and exposed may be subject to unexpected shading or funnelling from the local landform or structures a long way away. The only way to be sure is to measure the wind there objectively.

The cost and ease of carrying out this task make buying an inexpensive home weather station the ideal first step when planning to buy a home wind turbine.

Help To Locate My Home Wind Turbine is a post from: Weather Stations For Home

Why Did I Choose the WMR88?

I spent some time researching what was available before making my choice (but it is never easy as you can’t really be sure what you are going to get until it arrives and you physically see it), eventually I settled on the Oregon Scientific WMR88 home weather station.

WMR88 Base Station

The prime reason that I went for this particular one in the end was the combination of wireless sensors and a budget price.

Once I realised that wireless sensors were available it was a no-brainer for me. My house is not large and the prospect of running cables from a weather display inside to my small back garden was daunting.

There was no other comparable weather station that offered external wireless sensors and the cheaper models tended not to have any external sensors at all and were essentially glorified barometers.

So I bit the bullet and handed over my credit card details. The purpose of this review is to describe what I received in return.

What Sort of a Home Weather Station Did I Receive For My Money?

On opening the box I found:

• An excellent and thorough instruction manual.
• A weather display station (they call it a base station), with a mains supply and batteries (for back-up purposes only).

External sensors received with my WMR88 weather station

• A combined wind speed and direction sensor complete with a mounting bracket and a ‘U’ bolt with all required fixing screws. The sensor was small and light but very robust. According to the documentation there is an option to have this solar powered (this is something I have not yet investigated).
• A solid looking tipping-bucket rain gauge with a built in mounting base (again complete with all fixings necessary).
• A combined temperature and humidity sensor (supplied with a wall mounted bracket and fixings)
• To mount a personal hobby-horse of mine, Oregon supplied all required batteries (I wish other suppliers would take this simple customer-pleasing step).

Getting Setup:

The manual had a few tips for locating the external sensors (the rain gauge I simply screwed to a block of hardwood at the edge of my garden, the air temperature and humidity sensor I located under the eaves of the house to keep it out of direct sunshine and the wind speed and direction sensor I put at the top of my bird feeder pole right in the centre of the garden).

Getting each of the sensors to communicate with the base station was simple. They use radio waves and so each in each case the procedure was:

1. Fit the batteries
2. Select the radio channel via a switch in the sensor by the battery compartment (each sensor needs to be on a separate channel to avoid interference).
3. Install the sensors in their locations. The wind sensor mounting bracket needs to be pointed to the North (so I borrowed a compass from a neighbour to check that I had it pointing correctly).

That really was all that I had to do to get the system fully up and running.

How Does the Weather Station Display Perform:

The display screen itself is a good size 180mm x 110mm (and 40mm deep). It’s compact without being too crowded.

The WMR88 display screen

The beautiful blue-screen display unit (or base station) is divided into themed quadrants:

Top left are the forecast weather symbols for the next 12/24 hours. Top right is Wind speed and direction given both in numerical and intuitive graphical formats.

Bottom left is air temperature and humidity (as well as an indication of which sensor channel is beings displayed at the time).

Finally bottom right is for the barometric pressure (and pressure trend information), along with the time and the phase of the moon display.

All displayed values can be shown in the units of your choice (for me it’s Celsius, mB, and Knots but changing them is as easy as flicking a switch).

The base unit also includes on-board sensors for measuring indoor air temperature, humidity and of course air pressure, as well as having a built-in radio clock so I have never needed to set the time or date (as soon as it was powered up the internal clock tuned and set itself automatically).

An extra feature which I have not yet examined is the USB connection to computer which can be used for logging (for those interested in keeping long term records).

There are also various additional add-on accessories which can be purchased including a UV intensity sensor.

In Summary:

I couldn’t have been more pleased with what was provided I think it is a fantastic middle-level weather station for those who are interested but want something that is attractive and fun in its own right and (critically) doesn’t need any specialised knowledge or equipment to setup.

The whole procedure from unpacking to being fully up and running was perhaps an hour and a half (and that included the tea break).

If you are looking for a gift for someone with an interest, or just someone who has everything else, I can highly recommend the Oregon Scientific WMR88 as a fantastic choice for your home weather station.

So Why the Oregon WMR88?

• Wireless, easy to install system, but one that still takes weather measurement seriously.
• An attractive and fun display to have in any home which will quickly become part of your daily routine, just as it has with mine. I always feel that a way to check if you really value something is to imagine whether you would replace it if it were lost and I have no doubt, I need my WMR88.

My Oregon Scientific WMR88 Home Weather Station is a post from: Weather Stations For Home

A rain gauge is any device used to measure the amount and rate of liquid precipitation. The standard unit of measurement is the millimetre (mm). The type of instrument used is usually dictated by whether the weather station is manned or automatic.

Collecting Bottle:

In the former the calibrated collection bottle is still widely used. A calibrated bottle can’t be beaten for an accurate measure of rainfall amount, it never needs recalibrating and there is nothing much to go wrong.

An ornate version of a measuring bottle type rain gauge.

The collecting bottle does of course rely on regular checks in order that the rate of rainfall can be calculated and even then it will not be possible to track rainfall rates in real time.

Weighing Gauge:

These collecting bottles sit on a scale and the precipitation is measured by weight, this type can be linked to a recording mechanism (such as a simple chart printout or logged to a computer). When recorded in this manner real time rainfall rates can be recorded. The down side of this type of instrument is the cost and relative complexity making the purchase and maintenance costs much higher than other types.

The Tipping Bucket Rain Gauge:

Easily the most commonly used rainfall monitoring equipment at automated weather stations.

The precipitation fills one of two balanced buckets which (when a fixed and known amount of precipitation has filled the bucket), tips over and empties the water out of the base of the sensor, the action of tipping over then presents the second bucket to take over.

Inside a Tipping Bucket Rain Gauge

The twin bucket arrangement can be seen in the foreground balanced on top of the “A” frame.  When the bucket on the right has side has filled, it will drop down lifting the left hand bucket to the upwards position ready to take over. The cover that sits over the arrangement is in the background.

The capacity of the bucket is known and so a known amount of rain will cause the buckets to tip. Every tip opens and closes an electrical switch. External equipment (the weather station for your home, if you have one for example) will then count the number of switch operations and from that calculate the amount of rain, it will also keep track of the period over which the rain fell and so can report rainfall rates over the last hour or  12 hours or 24 hours etc.

This is the type of rain gauge used at almost every official weather monitoring site around the world. It is simple and reliable. The maintenance largely involves keeping it clear of debris. Calibration testing involves dripping a known quantity of water over a known period of time.

There have been question marks raised about their performance in torrential rain, it is suspected that they may under-read in extremely heavy rain because of the finite time taken to swap between buckets during a tip.

Choosing a good Location for Your Rain Gauge:

Regardless of the type of rain gauge that you choose the siting requirements are the same. The gauge is designed to measure precipitation from the skies only, so keep it well way from any structures which may allow water run-off (or wind-blown water run-off) to reach the measurement mouth.

Ideally they should be located away from solid surfaces (over grass is ideal) to prevent extremely heavy rain bouncing off the ground nearby and entering the gauge.

If you live in an area that will be subjected regularly to sub-zero temperatures then you may wish to consider a heated rain gauge. This prevents the gauge from becoming blocked with snow or ice.

How Do Your Results for Home Weather Station Rainfall Measurement Compare With the Experts?

One of the most enjoyable aspects of owning your own weather station is in comparing results with the big boys. The U.K. Meteorological Office has an excellent display of rainfall data from their rainfall radars why not see how the readings from your rain gauge shape up?

How is Rainfall Measured with My Home Weather Station? A Short Introduction to Rain Gauges is a post from: Weather Stations For Home

If you are a fan of the Weather Channel or just catch the occasional forecast after the news you will be familiar with the term wind chill, it’s usually only reported when the figure is spectacularly low but do you know what it is?

We all know the temperature difference that we feel between a still and a windy winter's day.

The intention of the reported wind chill figure is to advise what the temperature will feel like (as opposed the objectively measured air temperature which is always measured out of the wind).  This is arguably necessary because any movement of air over the surface of your body (or indeed any heat generating mass) will cause heat loss from the body. The rate of loss will be proportional to the speed of the wind and inversely proportional to the ambient temperature. In other words, the lower the temperature and the stronger the wind the faster the rate at which your body loses the heat it is generating and consequently the lower the temperature will feel. Wind chill (also referred to as the wind chill factor) is an attempt to report the perceived temperature in these conditions.

In contrast to directly measured weather parameters, wind chill is not an objectively demonstrable value. This is underlined by the fact that there is no one method used to calculate it. Different measures are used depending upon the application and upon which weather authority is referred to in  your part of the world.

In the U.K. probably the most commonly used formula to calculate it is the Siple & Passel formula. It is applicable when the ambient wind speed is 50 Knots or less and the ambient air temperature is 30 Degrees Celsius or less. Out-with these limits the wind chill formula does not apply.

The Siple and Passel Formula:

Wind Chill (Deg.C)= 0.045 x (5.27 x sqr (Wspd x 1.852) + 10.45 – (0.28 x (Wspd x 1.852))) x (T-33) + 33

Where: Wspd: wind speed in Knots, T= ambient temperature (Deg.C)  and sqr: square root.

The main bone of contention with the Siple and Passel formula is that it doesn’t factor in humidity which it is generally accepted does have a significant effect on perceived temperature, however the counter argument is that at low temperatures (which are the conditions under which the wind chill formula is applied) the humidity levels are low anyway.

There are many other wind chill formulae in use (the differences are geographical, for example the North American Wind Chill Index or the Australian Bureau of Meteorology’s Apparent Air Temperature).

As can be seen, this takes a little bit of calculating but there are many look-up tables available. There are some useful tables (one using the Steadman formula and one the newer Apparent Air Temperature can be seen at the Australian Bureau of Meteorology website).

The use of wind chill is contentious because you can get any number of values from the same weather conditions depending upon which formula or look-up table that you apply. But there is no denying the fun of working out the wind chill from the weather station in your home and appalling the neighbours with just how low it got last night.

What is Wind Chill and How is it Measured? is a post from: Weather Stations For Home

While perhaps a little beyond the scope of even the most ambitious owner of a home weather station it may still be of interest to hear about the instrumentation used by the professionals to measure cloud height.

Ideally weather forecasters use trained human observers to determine cloud height and cloud coverage. This is much trickier to do in reality than you might imagine. There is no handy graded scale running up into the ether and so they rely on cloud shape (different cloud formations form at different heights) and on local landmark knowledge.

Of course humans are expensive and so there are relatively few trained observers out there these days. The vast majority of professional weather stations therefore rely upon automated instrumentation for all measurements.

Automated cloud measurement is also routine at all major airports around the world (for fairly obvious reasons).

What Information is Included When Reporting Cloud Data?

For any given cloud group there are two defining characteristics to be reported, the height and the coverage.

The height is the average height of the cloud base above the ground. In the UK it is usually reported in Feet and depending upon the application of the report may be corrected to a height above sea level.

The coverage is a measurement of how much of the visible sky is covered by the cloud at this height. It is reported in Oktas (or eighths of the sky). For example if the cloud is overcast at a particular height (the entire viewable sky area is filled with cloud) then the coverage would be reported as 8 Oktas. Similarly if half of the sky is visible then the coverage would be reported as 4 Oktas (4/8ths of the sky is clouded over).

Cloud is grouped together in bands of height for reporting purposes and so a typical cloud report might be “3 Oktas at 1200 feet and 8 Oktas at 9,000 feet” meaning that the cloud at or around 9,000 feet entirely covers the sky from horizon to horizon and 3/8ths of the sky is covered with cloud at or around 1,200 feet.

How is Cloud Height Measurement Carried Out Automatically?

The device used is called a ceilometer. There are several different manufacturers of these devices but all work on broadly the same lines.

The ceilometer fires an infra red (IR) very narrow beam laser pulse into the sky. The cloud (which is composed essentially of water droplets suspended in the air) reflects the pulse back down to the same instrument which detects its return. The ceilometer keeps a highly accurate track of the elapsed time between the IR pulse being emitted and it being received back again.

The IR pulse travels at the speed of light so it is a simple matter to calculate the distance away that the target (the cloud in this case) must be:

Distance = speed x time

Speed and time are known, therefore distance can be calculated (speed x time will then need to be divided by two of course because the IR pulse must travel from the ceilometer up to the cloud base and back down again).

So Cloud Height Measurement Should Be A Doddle, Right?

This makes that device sound like doddle to design but actually it has taken years to develop reliably accurate cloud height ceilometers and it’s only really in the last 10-15 years that they finally reached the levels of dependability that meant they could be trusted at unmanned weather locations and airports.

A typical ceilometer, below each of the two circular windows is a large lens. One is used by the laser transmitter to emit the IR pulse the other will focus the returned pulse onto the highly sensitive receiver.

Among the problems that had to be overcome were:

All air holds moisture to some extent or other so the correct wavelength of IR which would pass through humid air or mist but be reflected by the larger water droplets which form cloud had to be determined. In addition the laser diode within the ceilometer which generates this very pulse has to be very accurately temperature controlled in order to maintain the required wavelength. Similarly the receiver diode (which detects the returned pulse) has to be incredibly sensitive (only the tiniest imaginable portion of the transmitted IR pulse will return) and it also has to do this without being swamped by natural sunlight. This was achieved through temperature matching with the transmitter diode and additional filtering techniques.

Most ceilometers will have a maximum range between 25,000 and 50,000 feet and will take measurements every 60 or 120 seconds. Each measurement results in either a cloud height reported (or of course no cloud reading if none is present). Typical cloud height measurement accuracy will be in the order of 10 to 30 feet.

Another example of a ceilometer, this is one points at an angle in order to minimise direct overhead interference from the sun but the principle and method of measurement are unchanged.

A ceilometer fires a laser directly upwards and receives the return reflection. This means that it can only measure cloud directly over the instrument.

How is Cloud Coverage Calculated?

You’ve probably already guessed, by computer algorithm. Either calculated at the sensor itself or remotely, but in either case it looks at the history of cloud heights reported and infers the coverage. It can be rightly argued that over time as the wind blows the cloud over the top of the instrument the ceilometers will only ever have exposure to a strip of the sky, it will never be able to monitor from horizon to horizon and so the coverage can only be an estimate. There are trials being conducted which are using both ceilometers and high resolution cameras together to try and improve on this. The cloud height is measured by the ceilometers and the camera scans the visible sky area taking photographs which are then computer analysed to try to determine the coverage. Infra red cameras are used as this allows the monitoring to be carried out during the night as well as in daylight hours.

For the home weather station enthusiast there are many excellent guides available to help you identify different cloud types and estimate heights. The U.K. Meteorological Office has an excellent guide to identifying cloud.

With experience you can probably at least match the current state of the automation in estimating cloud height and coverage as nothing beats the trained mark-1 eyeball.

How Is Cloud Height Measured? is a post from: Weather Stations For Home

Accurate use of a barometer to monitor changes in barometric pressure is the lynchpin of weather forecasting.

source:Flickr

This short article is intended to be of use to anyone who is thinking about buying a barometer for their own home or as a present. It will give broad overview of what is available and hopefully point you in the direction of the type that will suit you best.

Let’s start with a short introduction:

What Is A Barometer?

A barometer is a device that measures barometric pressure, what kind of fool do you take me for?

What then is barometric pressure?

It is the pressure exerted by the weight of the air above. It’s easiest to understand if you picture a column of air stretching up into the atmosphere.

The downward pressure of that column is what is being measured by a barometer. This incidentally explains why barometric pressure (otherwise referred to as atmospheric pressure) changes with height.

If you are standing at the top of a mountain the column of air is shorter than if you are standing on the valley floor and therefore the pressure exerted is less.

So, since pressure varies with height, if you move you barometer from one place to another you will almost certainly be at a different elevation and therefore won’t you change the reading? You are absolutely right (how astute you are).

To avoid every meteorological organisation in the world having to mount their barometric pressure sensors at the same elevation all readings are corrected to sea level. Whenever you hear a pressure figure given in a forecast it has been corrected to sea level.

A formula is used to adjust the reading given by the barometer to derive the pressure it would have read had it been located at sea level.

Remembering that barometric pressure is the weight exerted by a column of air will help understand that almost always the adjusted figure will be higher than the physically measured one.

What Does A Barometer Measure?

The unit used for atmospheric pressure measurements is the millibar (mB). In scientific publications you will often see the hectopascals (hPa) unit used instead (but it couldn’t be easier to convert, 1mB = 1hPa). The only exception is the in the USA where they still use millimetres of mercury (mmHg) for their barometric pressure measurements.

If you are wondering how to adjust your local barometric pressure reading to sea level then there is a fairly fearsome formula to do so, but broadly speaking 10 meters or 33 feet of height corresponds to 1mB.

Therefore if your measurement location was 50m above sea level then you would add 5mB to your measured reading. In reality the formula also factors in air temperature (which will change the density in the column of air above and therefore also change the pressure-per-metre of air).

However for all practical purposes 10m/33ft per mB will prove accurate.

Ok, that’s probably a lot more than you wanted to know. But at least now you can hang around in front of your barometer waiting for some fool to come past who you can impress with some technicalities. Let’s look at what types of barometer are available.

Mercury Barometer:

It may still be possible to buy a mercury barometer in the shops but if so I haven’t seen any. They look a lot like a committee-designed thermometer:

mercury barometer

They are extremely accurate but probably a non-starter for the home, people are (rather sensibly) reluctant to have large quantities of toxic substances in fragile glass containers on their walls.

The Household Favourite, the Wall-Mounted Barometer Dial:

A rotating needle points to the current pressure and usually the words “Rain”, “Change” and “Fair” appear with ill-deserved confidence in bold text. More accurate might be “low pressure” “middling pressure” and “high pressure”.

The device itself holds no memory of the recent pressure history and so it’s a mystery known only to the manufacturers exactly how they know whether or not it is going to rain.

In terms of accuracy, they should be pretty good, they all work using an aneroid sensor  (aneroid simply means without liquid, it is essentially a sealed box that expands and contracts with changes in external air pressure, this movement is transferred to the dial on the front of the display).

They will require periodic adjustment but this is a straight forward process, much like setting an alarm clock.

Of course they come in all kinds of styles from the beautiful antique marine style brass dial to the plywood-mounted with the warning “Frae Bonny Scotland” printed above. You pays your money and you takes your choice. Prices range accordingly of course.

wall mounted barometer (the inner scale here shows pressure in mmHg)

Digital Barometer Pressure Sensors and Displays

These days there are a large range of inexpensive LCD style barometer displays, often incorporating indoor temperature and even little pictograms of storm clouds (the digital equivalent of the barometers’ outrageously optimistic rain, change or fair and probably not much more reliable but definitely more fun).

I have one that combines its function with that of being a wireless doorbell, it cost £15 and is every bit as accurate as these facts imply, but I still enjoy using it.

Digital sensors do come in all styles and price ranges. If you buy a good one you can typically also get graphs of the pressure trends and automatic adjustment for sea level pressure.

digital barometer pressure display (with pressure trend information)

The Rotating Drum Barograph:

The king of barometric pressure measurement and my personal favourite is the rotating drum barograph. It looks a bit like the seismographs that you see in earthquake disaster films. Depending on the model chosen you will typically have a chart on a drum that rotates over a period of a week or a month and is linked to an aneroid barometer which in turn moves an ink pen up and down the rotating paper chart in response to pressure changes.

They are usually clockwork (part of the charm of ownership is the routine of winding up the rotating drum mechanism). The pressure is set with a small manually adjusted knob which shifts the physical position of the pen on the paper charts. Once set it very rarely needs resetting.

Some models use a disposable felt-tip pen for the trace on the charts, others the more traditional nib and ink reservoir. The latter is lovely and feels more in keeping with nature of these instruments but I have never yet seen one that wasn’t caked in ink smears. Replacement pens and chart paper are generally available (for some reason ship’s chandlers often seem to sell this type of equipment).

They are extremely sensitive, I once worked in an air conditioned office which had one and it was possible to tell if the door to the office had been opened because there would be a small kick in the pen trace on the chart where the pen had reacted to the pressure change in the room caused by the door opening.

Rotating drum barograph, the aneroid barometer is the silver coloured column of disks below the pen-arm.

Rotating drum barographs are undoubtedly objects of beauty (and usually extremely accurate too) unfortunately this is typically reflected in the price, expect to pay upwards of £600 for a good one, but then these are heirlooms.

Ultimately, you choose the barometer that you can live with and matches your budget.

Dummies Guide to Barometric Pressure and How to Choose From the Barometers On Sale is a post from: Weather Stations For Home

When setting up home weather station instruments, the most critical part is location, location, location.

Because one of the most important determinants of how accurate the readings will be from your weather station sensors is where you choose to site them.

A wind speed sensor (anemometer) will only measure the wind speed where it is located, if you place it in a sheltered spot then you will get a sheltered reading. An obvious point perhaps, but one that can’t be overstated in importance.

The purpose of this short article is to provide guidance on critical factors that should be taken into account when selecting suitable locations for weather monitoring equipment.

Unless you are very lucky you will find that you will have to make some compromises on the ideal location (the perfect location is seldom physically practical) but this guidance will hopefully still be useful in helping to choose the best available sites that you can. Preferably sites that allow accurate measurement and easy access for maintenance too.

In addition to my own personal experience, I have also used official sensor location guidelines. Where quoted, (in bold italics), recommendations by the World Meteorological Organisation (WMO) are taken from: Guide to Meteorological Instruments and Methods of Observation. Seventh Edition (WMO-No.8).

Home Weather Station Air Temperature Sensor and Humidity Sensors:

These sensors are usually sited together and must be installed in a shaded location. Ideally they should be placed in an enclosure designed to provide shade but also to allow airflow around the sensor. There are two types of these enclosures in common use, the Stevenson Screen and the Radiation Shield (the Radiation referred to in this case is of course solar).

A typical Stevenson Screen

The screen illustrated here is the type and size that would be used at an official weather reporting site, for the typical home it would be much too large. Cut down versions are readily available. The sides of the enclosure are made up of two sets of opposed louvers (i.e. 2 sets of slats aligned in opposition to each other) which allow the ambient air to circulate freely within the enclosure but prevent rapid movement of air over the sensors inside even in strong winds. The enclosure is painted white to reflect the sun’s rays.

The wooden Stevenson Screens are very attractive and are still used by official weather organizations because of their stable thermal properties (even on a sunny day the heating and cooling of a wooden screen is very small compared to other materials, this is of course vital when you are measuring air temperature). The downside of the wooden screen is maintenance. Within a few years these screens will need re-painting (and this is no small job, believe me). There are fiberglass versions of these enclosures around now, they don’t look as good (in my opinion) but they don’t need repainting and there is no evidence that they distort temperature readings.

If you use a Stevenson Screen then it also allows you the space to fit a mercury thermometer alongside your weather station air temperature sensor. This is always useful for an accuracy check.

A Radiation Shield (with an anemometer and wind direction sensor above it)

The Radiation Shield is generally much more compact and is usually supplied with a ‘U’ clamp arrangement so it is easy to mount. The sensor sits in the middle of the pagoda-like column of fiberglass or plastic plates. The structure essentially performs the same function as the Stevenson Screen, it provides shade, reflects solar radiation and keeps the sensing element out of the wind and rain.

Unlike the Stevenson Screen it is almost maintenance free, a clean once in a while is all that is required. There is of course no room for a mercury thermometer but it is undeniably the more practical option for most people.

Choosing a Good Location for Your Air Temperature /Humidity Sensors:

The WMO recommendations are as follows:

“For general meteorological work the observed temperature should be representative of the free air conditions surrounding the station over as large an area as possible, at a height of between 1.25 and 2m above ground level.”

“The best site for the measurements is, therefore, over level ground, freely exposed* to sunshine and wind and not shielded by, or close to, trees buildings and other obstacles”

*”freely exposed” refers to the Stevenson Screen / Radiation Shield, not the sensor itself.

“A site on a steep slope or in a hollow is subject to exceptional conditions and should be avoided.”

“Observations of temperature on the top of buildings are of doubtful significance and use because of the variable vertical temperature gradient and the effect of the building itself on the temperature distribution”

Depending upon the type of sensors that you have you may find that you certain limitations pertaining to cable length. It may not be possible to extend the cables provided (at least not without re-calibration).

The temperature and humidity sensing equipment should be sited at a location that is representative of temperature/humidity for the installation area. For example, at a rural location the sensor should be installed over grass. Similarly in sandy-desert locations they should be sited over sand.

The sensors must be located away from any local heat sources (e.g. central heating vents). Note that the sensors should be as far from any such sources as possible because warm air may be carried down-wind to the instruments. This requirement also means that the surface below the sensing equipment should not be constructed from materials that will reflect/radiate heat. For example, in a garden, the sensors should ideally be located over grass not a patio. The concrete in a patio will spend all day absorbing heat from the sun and during the evening will radiate that heat back into the air. If your temperature sensor is sitting above the patio then you will get distorted readings.

The instruments should be sited in a “free-air” location, i.e. a site that has as unrestricted air movement around and through it as possible.

They should be easily accessible for periodic maintenance.

The Stevenson Screen / Radiation Shield is a relatively fragile construct and so is vulnerable to impact damage. Therefore it should be sited well away children’s play areas.

Barometric Pressure Sensor 

A Typical intrinsic type of pressure sensor (usually mounted directly on a printed circuit board).

If the weather station that you have purchased is one in which the barometric pressure sensor is intrinsic to the display unit then you have no choice about this, the pressure sensor will be located wherever you place the display. This type of arrangement is generally used with fairly inaccurate sensors however this type of sensor should be perfectly satisfactory for reporting the general pressure trend.

If your pressure sensor is separate to the display unit then here are some thoughts about where and how to site it.

Pressure Transmitter

This type of pressure sensor comes in all shapes and sizes. Each will typically have an electrical connection for power and signal (the orange connector block in the bottom right corner of the picture above) and an airline connection port (bottom left).

Ideally you want to be measuring the outside air pressure (this is especially important for air conditioned buildings or other locations where there is a significant variation between the air pressure inside and out). The sensor itself can still be located inside and a plastic airline run from the sensor to a suitable outside location.

The external end of this airline should be terminated in a static pressure head. This is a vented end-piece which performs the dual functions of preventing water ingress into the airline and avoiding a pressure drop within it caused by wind blowing over the top of the open airline (the “Venturi” effect). If you blow over the end of a tube which is open at one end then the pressure within the tube drops. In this instance the open end of the tube is the airline connection port on the pressure sensor. If this sensor was simply placed outside exposed to the elements then any movement of air across the airline connection port would cause fluctuations in the pressure measured by the sensor.

An example of a static pressure head (the sensor is the grey unit at the top and the static pressure head the disk shape structure, the airline runs through the interlinking tubing)

Where I Placed My Own Home Weather Station Pressure Sensor

Personally, my pressure sensor is located within my Stevenson Screen. I do not use a static pressure head (the sensor airline connection port is simply left open within the Stevenson Screen itself). Whether or not this will suffice for any given location will depend upon how windy it is. In a very exposed location you may well find that pressure fluctuates on a windy day even within the Stevenson Screen. If so then an airline from the sensor to a static pressure head is the answer.

When installing the plastic airline it is strongly advised that a large ‘U’ bend in the tubing is incorporated immediately before termination at the static pressure head in order to trap any water that gets in (rather than let it get into the pressure sensor).

Note that the sensor will measure air pressure at the instrument height only, irrespective of where the external airline is run to. The weather system processing equipment / software will then correct this value to give air pressure readings at sea-level (QNH).

Choosing a Good Location for Your Barometric Pressure Sensor:

Depending upon the type of sensor that you have you may find that you certain limitations pertaining to cable length. It may not be possible to extend the cables provided (at least not without re-calibration).

Keep it easily accessible for periodic maintenance.

The static pressure head should ideally be located in free-air with good airflow around it.

The static head should be located away from walls and the edges of roofs, as the wind-rush up the side of the structure can present “Venturi” effect problems. The reliability of the static pressure head in negating the effects of vertical movements of air is less effective than for the horizontal component of airflow.

The static head and associated airline should also be accessible for periodic inspection and maintenance.

Wind Speed and Direction Sensors:

These are probably the trickiest of the sensors for the home user to site and there is certainly no one-fix solution for all cases.

The two key requirements are

1. Unobstructed exposure to the prevailing wind direction.
2. Easy access to the sensor for maintenance.

You want to get the sensor as far clear of any obstacles as you possibly can (without having to install a phone mast in your back garden). When choosing how and where to put the sensor(s) bear in mind that the turbulence associated with any vertical surface (such as the side of your house) extends for many meters above the top of that surface. The wind will hit the side of the house and then travel vertically upwards and over the top of the wall. If you stand on the roof on a windy day you will find a dead area with virtually no wind close to the edge of the wall. This is the dead spot caused by the wind rushing up the wall and over the top of your head. If you place the sensor here you will never get reliable readings. You need either height above the house or distance from it.

A combined wind speed and direction sensor.

An instrument where the speed and direction sensing elements have been separated.

Choosing a Good Location for Your Wind Speed and Direction Sensors:

The WMO recommendations are as follows:

“ The standard exposure of wind instruments over level, open terrain is 10m above the ground”

where “open terrain” is defined as:

 “the distance between the anemometer” (wind speed sensor) “and any obstruction is at least 10 times the height of the obstruction”

“Wind observations that are made in the direct wake of tree rows, buildings or any other obstacle are of little value and contain little information about the unperturbed wind.”

“An optimum location is one where the observed wind is most representative for the wind over an area of at least a few Kilometres”

WMO Recommendations Relating Specifically to Wind Measurement at Sea:

“On fixed platforms and ships, it is of the utmost importance that wind sensors be exposed sufficiently high above the platform and its superstructure to avoid the often extensive influence of the platform on the local wind structure”

These recommendations from the WMO are clearly only a wish-list for the home weather station installer but they do at least give a good idea of the important criteria. Before choosing the spot for your wind sensors it would be worth finding out the prevailing wind direction for your area. Then choose your sensor exposure based on this (remember that wind direction is always reported as the direction from which the wind is coming). For most people it will not be possible to site the sensors such that they have free exposure to wind from all directions so your options then are either to site your sensors such that they have free exposure to the prevailing wind direction (that way they will give reliable readings most of the time) or if your weather monitoring system (and budget) are flexible enough you can have multiple wind sensors, each of which has a different exposure providing reliable information whenever the wind direction favours them individually.

As with the previously referred to sensors there may be cabling limitations associated with your particular instruments.

The sensors must be accessible for periodic maintenance.

What Do I Do Next?

If you are looking to get started with setting up a weather station, or you just need additional sensors for your existing kit, take a look at the products on the sidebars. They will provide extra technical specifications and show you the current choices in the marketplace.

Feel free to leave a comment with any questions on setting up your home weather station instruments.

Setting Up Home Weather Station Instruments – How To Find The Best Weather Station Locations is a post from: Weather Stations For Home

Beaufort Scale (Source: Wikipedia)

In 1805, Francis Beaufort created a scale for describing the strength of wind. His purpose was to give sailors a common way to reference this critical element of sailing.

Beaufort was a British naval officer and a surveyor and his dogged pursuit of support for his scale led to his immortalisation of sorts as the scale gas been in use ever since.

The scale of 0-12 directly relates to ever-increasing wind-speed, but originally referred to the impact of the wind on the sails of a Royal Navy Man of War rather than the set wind-speeds we can measure so readily today.

It took until 1830 for the scale to be taken up officially, by which time Beaufort was a senior figure in the admiralty. His eponymous scale was first used in the famous journey taken by Charles Darwin in The Beagle, setting sail in late 1831.

While its importance was primarily for maritime navigation in an age of sail, it proved immensely useful as a means of providing internationally consistent meteorological measurements and subsequently, forecasts.

Above and beyond the Beaufort scale 12 lies the start point for hurricanes – for which the Fujita Scale (or F-Scale) was created.

The Beaufort Scale – why it was created and why we still use it as to measure wind speed today is a post from: Weather Stations For Home

Can snow keep you warm?

Absolutely yes. You only have to think of Eskimos and igloos to start making sense of this. Carving out ice blocks and building containers actually traps heat and provides shelter from the environment – this is not a myth.

An example of snow’s insulating abilities lies much close to home. The last couple of winters has seen a lot of snow fall in the UK, and you may have notices that with two feet of snow on your roof that your house was actually able to stay a little warmer than when the roof was clear. Additionally, the snow dampened outside noise.

Snow and ice are quite different in their properties considering they are composed of the same thing and you can observe this in nature – the temperature underneath frozen ground can have frost extending perhaps six feet into the ground. But if there is a thick layer of snow, the ground is much less likely to be frosted to anything like that depth. This is one reason why football matches can proceed even when there has been fresh snow fallen overnight – that fresh light layer actually protects the ground from freezing and making our national sport impossible.

Is It True That Snow Can Keep You Warm? is a post from: Weather Stations For Home

Of course you can. The colours of the rainbow can be remembered from:

• Richard
• Of
• York
• Gave
• Battle
• In
• Vain

Rainbow Brite and Color Kids Source: Wikipedia

Source: Wikipedia

Can you Name the Colours of the Rainbow? is a post from: Weather Stations For Home

Sun dogs and moon dogs are similar phenomena, occurring (obviously) at day or at night around the sun and moon respectively. They are bright spots that you get on the sides of the sun or moon when there are thin ice crystal clouds in our atmosphere – it’s an optical trick.

This can appear as three suns at first glance, but it’s just a sun dog, of if you want the scientific name – a solar parhelion. Here’s what causes it – hexagonal ice crystals falling from high level with their longest axis vertical. If you were to measure them you’d see they were at 22 degrees on either side of the sun.

Another name for sun dogs is mock suns – but if you want to observe these, the old rules apply. You never look directly at the sun and the best approach is to use the old pinhole trick of casting a shadow with a sheet of card with a pin-prick through the middle – you will see the light caset from the sun in a way that you can comfortably view and even photograph (if you have enough spare hands within your group). The same experimental set-up is excellent for observing solar spots.

What’s a Sun Dog And Should I Hide from a Moon Dog? is a post from: Weather Stations For Home

The sun plays a dominant part in all our lives – responsible for all life on our planet. Its gravity holds our planet in orbit and its heat warms us as we rotate. we rarely give much thought to the sun as an entity in its own right – here in Scotland it can seem a very dim far off thing some times, only to surprise us on hot summer days as we turn lobster red.

Let me address the second part of the question first in case you were starting to worry – no, it will not be burning out soon. It’s about half-way done as a star, with another five billion years to go. Your inheritance will still make a difference, so don’t go spending it in anticipation of Danny Boyle’s vision in the film “Sunshine”. Sydney Harbour will not be icing over any time soon.

The sun is immensely large on an earthly scale, you maybe don’t appreciate just how big it is in comparison to us. Its diameter is one hundred times that of Earth and its mass is 334,000 times greater. It’s not that huge on a galaxy scale though, fitting into the category of small but willing stars known as yellow dwarfs.

So how far away is the sun? About eight minutes right? (Hadron Collider permitting). If the sun were the size of a basketball, we would be 86 feet away. And Earth would be 0.09 inches across. By comparison, the moon would be orbiting Earth at a distance of 2 and a half inches.

How Big is the Sun and Will it Burn Out Any Time Soon? is a post from: Weather Stations For Home

When I was being taught physics at high school, it was strictly metric throughout the early eighties. My mother talked in Fahrenheit and unbelievably my wife continues to talk in Fahrenheit today. For me there was an inherent beauty in the idea that you could apply a linear scale to something so fundamental to life on Earth.

pic: Chris Bloke under CC BY

Newtons Laws proven by experiment

.

When I was eleven I was astonished to learn that Newton’s Laws could neatly encapsulate the motion of particles in the same way as the movement of the planets – it seemed beyond belief that nature could be so mathematical, which to me meant beautiful.

The surprises continued when I learned that the Celsius scale starts at the point where water transforms from solid (ice) to liquid (water) and ends where it transforms from liquid into gas, in other words the scale of zero to one hundred. Of course the scale goes beyond in both directions, but I remember wondering why it stopped at 273 degrees below zero and yet there seemed no upper limit. This also did not square with my view that in an infinite universe there was surely no end of variation in the laws of physics. But I was flatly assured that this was not the case and that the laws of physics are constant everywhere. I have not yet spoken to my old physics teacher about the recent furore in the Hadron Collider when it appeared that there were particles timed as travelling faster than the speed of light.

But I digress.

To all intents and purposes they ARE the same thing – the centigrade scale was invented by the Swede Anders Celsius in 1742 (he was an astronomer interestingly enough). Around two hundred years later, the scale was renamed in Mr Celsius’ honour, thus rendering the term centigrade obsolete.

Having said that, I still prefer to say “centigrade” rather than “Celsius”. You say tomato, I say Fahrenheit (the origins of which are even more bizarre – I’ll save that for another post). I still think it’s a beautiful invention.

Are Celsius and Centigrade Not Just Two Names for the Same Thing? is a post from: Weather Stations For Home

Peary at the North Pole (courtesy flickr.com)

So how many time zones separate the North and South poles? Yes, it’s a bit of a trick question, but like so many things, there is an official answer cooked up by a committee that ended up getting its own way.

Of course all time zones converge at the poles, so on theory you could speak via multiple satellite hops to a friend while each of you stands on one of the poles, each take a step to the left and be 12 time zones apart, then take two steps to the right and each of you has shifted into the other’s time zone.

So just what time is it at the North and South poles? Michael Palin could tell us – the answer is: the same time as it is in London. Just as Greenwich Mean Time comes from the famous observatory in London (think about that for a moment – a totally arbitrary east-west position to call the origin) so the time at the Poles was agreed internationally as the same time as London – Universal Coordinated Time (UTC).

What’s less obvious is how far you walk from the Poles before the time zones kick in again…

…answers on a postcard to the usual address please.

How Many Time Zones Separate the North and South Poles? is a post from: Weather Stations For Home

The reason clock weather stations are so popular is that they are as inconspicuous as a kitchen clock and it’s only on second glance that you see that they are something more special than that.

A typical clock weather station will have both a barometer and a thermometer, sometimes as two sub-dials on the main face. I don’t much like the clock stations that try to assert themselves too hard and make the clock twenty four hour or looking as if it has come straight from a Red Army barracks. We get it – it’s not just a clock. But it is! I much prefer the clock to look like a clock and yet have these extras.

I’ve talked elsewhere about my disdain for internal thermometers in weather stations and how they are of little use where a house has central heating in every room and we all warm ourselves more than any previous generation, thus rendering the internal thermometer not particularly useful for helping to form a view on changes in weather conditions. Better than nothing and I suppose it helps you check your room temperature.

Much more useful is the barometer – even indoors, you can tell a great deal from observing the change in direction of a barometer and indeed the rate at which it rises or falls. Even the simplest of aerobic barometers can help you assess the weather and in the age of computers, it is something of a wry pleasure to gradually learn how to interpret the changes in pressure and how that relates to impending changes in weather conditions.

The more expensive clock weather stations go a little bit further – my single favourite extra feature is when the clock is kept to the correct time by the nearest radio clock transmitter. It is a bit spooky to observe this when the clocks go backwards or forwards (yes, I was having a whisky and it was most amusing to see the hands spinning round to catch up – a bit like a transition scene in a movie). In this sense there can be a little argument – this kind of clock weather station is a better clock than a clock.

Clock Weather Stations is a post from: Weather Stations For Home

The ideal home weather station should be somewhere between the two forbidding extremes of low-end stations that are little more than throwaway tots and the top-end station favoured by the semiprofessionals (and several retired meteorological experts). The challenge is to find a station that gives you something quickly and still has something in reserve for you to come to grips with. I know all too well the feeling that comes with paying good money for a weather station and finding out within three months that I had exhausted its capabilities.

Now while none of us has a crystal ball it is reasonable to draw up a list of must-haves for what I would consider a good quality home weather station.

At a minimum it must have remote sensors – without these you are still really in joke territory – there’s only so much weather you can predict keying off the variations in your central heating. Nowadays that means wireless remote sensors, all feeding back to the main base station positioned somewhere both discreet and accessible. In my house i have the station positioned by the door – I like it to be the last thing i see before I leave, but you can put it anywhere than makes sense to you. Many people place theirs in the kitchen, where it becomes a conversation piece.

So – sensors. While we cover these in much greater detail elsewhere in the site, let me just outline what I regard as the minimum set:

1. rain gauge – pretty fundamental in the UK. Up here in Scotland, it seems most conversation about the weather begin with a mention of whether it has been raining or not.
2. anemometer – I know these can look a bit silly in a small-scale (which is what this mid-range is limited to), but they do an adequate job. Let’s face it, changes in wind direction are almost impossible to track manually, so this is one device that may surprise you with its results and underlying patterns. We’re talking here about both wind-speed and direction in a single sensor.
3. remote thermometer! a little like the cuddly toy in The Generation Game, this is the first thing most people think about. In terms of surprises, temperature is one of the few things I can just about guess by walking around my garden. But need it you do.
4. atmospheric pressure – the granddaddy of weather forecasting sensors and the one which you could use on its own for weather forecasting, certainly of the finger-in-the-air variety. As a fan of the Patrick O’Brien Aubrey-Maturin novels, I love the way that |Aubrey spends more money on accurate barometers than he does on any other object he owns and can carry.

What Should Every Home Weather Station Include? is a post from: Weather Stations For Home

rain water

You will often hear people talking about the purity of rain water and how there is nothing healthier – indeed many people regard it as superior to what comes out of their tap at home. In fact it is usually the other way around – tap-water is subject to incredibly stringent tests following purification.

Rain water on the other hand is very clean, but not completely! Rain drops come into being by condensing from water vapour onto something else, a speck of dirt or salt – this stays with the drop all the way til it reaches the ground. When that water dries up, the debris (albeit very small) is left behind.

Before modern mass purification systems, rain water was the staple source of the freshest water, and certainly, in poorer countries in hotter regions, what little water does fall usually exceeds local supplies, especially in areas with inadequate or damaged infrastructure.

It is also fair to say that even here in the United Kingdom, falling rain water is cleaner than whatever we try to catch it in, such is the level of concentration of impurities.

Is Rain Water The Purest You Can Drink? is a post from: Weather Stations For Home

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Weather forecasting with a splash of colour. Feast your eyes on the colour-changing weather forecast icons of this Atomic projection clock. ….read more

Oregon Scientific BAR339DP Daylight Weather Projection Clock is a post from: Weather Stations For Home

 

Bringing the sundial right up-to-date! This solar charging clock is radio controlled which ensures it will always be accurate to the second and you’ll never have to set the time again. Including a calendar and single alarm.

Oregon Scientific BAR332ES +ECO Solar Charging Weather Station is a post from: Weather Stations For Home

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humidity via up to 3 transmitters (max. 100 m),
indication of indoor temperature and humidity,
max.- min.- function,
weather forecast,
tendency of atmospheric pressure,
bar graph indication of atmospheric pressure of the last 24 hours,
radio controlled clock with date, time zone ±12 hrs.,
measuring range temperature outdoor -40..+60°C (-40 ..140 °F), indoor -10..+60°C (14..140 °F), reversible °C/°F, humidity 1..99 %,
for hanging or standing, ….read more

Diva Plus Wireless Weather Station is a post from: Weather Stations For Home

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A black, sleek and stylish electronic weatherstation that projects the time to any wall or ceiling.Features also include indoor thermometer and hygrometer, calendar and alarm clock.This weather forecaster is an ideal gift and would compliment any room.Features:-Electronic weather forecasterProjection clock (red LED) LED backlight Indoor thermometer and hygrometer Perpetual calendar with day of week Snooze alarm clock 12 hour thermometer trend Requires 4 x AAA batteries (not included) ….read more

Science Museum Projection Clock with Weather Forecaster is a post from: Weather Stations For Home

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….read more

Eddingtons Weather Station Wall Clock is a post from: Weather Stations For Home

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transmission of outdoor temperature via up to 3 transmitters (max. 100 m),
indication of indoor temperature and humidity,
max.-min.- function with time and date,
weather forecast by symbols and Weather boy (15 variations of clothes),
tendency of atmospheric pressure,
radio controlled clock with date, alarm and snooze function,
time of sun rise and sun set, indication of moon phase,
backlight,
measuring range temperature outdoor -40..+60° (-40..+140°F), indoor -10..+60°C (+14..+140°F), reversible °C/°F,
humidity 1..99 %,
for hanging or standing,

equipment: outdoor temperature transmitter 30.3147.IT,
batteries 2 x 1,5 V AA display station, 2 x 1,5 V AA transmitter
weather forecast by weather boy
125 x 90 x 30 mm, 127 x 38 x 18 mm, 430 g ….read more

Weather Boy XS Wireless Weather Station is a post from: Weather Stations For Home

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La Crosse Technology Meteotronic Weather Prediction Centre

Specification:-

DCF Radio controlled time and date
Time alarm
Time zone change
4 Day weather forecast (some regions may receive 3)
Permanent display of MINI/MAXI temperature forecast
19 Pre-registered European cities
Indoor Temperature from 0 – 50°C
15 Icons for day forecast and 15 Icons for night forecast
4 Day Rain Probability in %
Wind speed with wind direction indication
Station: L x W x H = 142 x 26 x 136 mm

….read more

LA CROSSE TECHNOLOGY METEOTRONIC WEATHER PREDICTION CENTRE PLUS is a post from: Weather Stations For Home

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….read more

LA CROSSE TECHNOLOGY PROFESSIONAL WEATHER CENTRE IT+ WS1600 is a post from: Weather Stations For Home

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This high value doubler kit from La Crosse Technology includes both a weather station and a projection alarm clock. between them, they’ll tell you what you need to know for time and weather information at a glance.

The WS9040 weather station tells you temperature both inside and out (includes a battery powered outdoor sensor) and provides detailed weather forecasts featuring barometer trend read-outs on its LCD display.  

The clock (which is entirely independent of the weather station – you can keep one and give the other away!) is radio-controlled, meaning you’ll never be late as the time is constantly adjusted to the exact correct time automatically.

The WT5160 projection clock is great for the bedroom and allows you to see what time it is at a glance.

The projection feature is good fun for night-time use, giving you clear, easy-to-read data. It saves having to switch the light on to see what the time is.

It provides one more thermometer so you’ll be able to confirm with your WS9040 if it truly is as cold as it feels outside your duvet. ….read more

La Crosse Technology WS9040 Weather Station and WT5160 Projection Clock Reviews is a post from: Weather Stations For Home

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Three-part set, consisting of a base station, a USB transmitter and software. Exact weather forecast data can be selected via the internet for up to 5 places, from about 20,000 cities in Europe, North America, Japan and Australia. ….read more

Hama WDS300 USB Weather Data Station is a post from: Weather Stations For Home

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….read more

Green Science Weather Station Childrens Creative Science Art is a post from: Weather Stations For Home

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The Oregon Scientific WMR80 is the classic mix of base station and full set of remote wireless sensors. You can construct a high quality local forecast using the readings from monitored air pressure, temperature and humidity, rainfall and wind speed.

WMR80 also provides humidex and dew point data and provides a digital rolling barograph.

You can enter your current altitude and the device will provide constant updates of height above sea level and display air pressure in mb/hPa or mmhg.

WMR80 comes with three different sensors: to provide temperature/humidity and even UV readings at a transmission distance of up to 100 metres.

Weather forecasts are shown in multilingual diagram form, with a clock and alarm function.

WMR80 with sensor pack

For more technical details, you can consult the Oregon Scientific WMR80 Professional Weather Stataion manual here.

Oregon Scientific WMR80 Professional Weather Station is a post from: Weather Stations For Home

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Oregon Scientific ultra thin weather station (battery powered). Inside and outside temperature monitoring with a hygrometer. Seven day weather forecasting abilities. Comes complete with a battery-powered wireless temperature sensor suitable for use outdoors. ….read more

Oregon Scientific Ultra Thin Weather Station is a post from: Weather Stations For Home

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W-2001 World Wireless Weather Station with Internet connectivity
This model can display a wide range of data and is ideal for a wide range of uses. The smart free standing display is bright and can also be wall mounted.The external temperature/humidity detector can be mounted outside and is wirelessly connected on UHF. A complete weather forecaster and weather station in one very compact and portable package. You could even take it on holiday! ….read more

Watson W2001 weather station with 5 day forecast is a post from: Weather Stations For Home

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Browse Other Wireless Stations

The beauty of the Sinus bundle is the outstanding number of features. Most importantly it provides a weather forecast and tendency of atmospheric pressure, plus absolute and relative atmospheric pressure with a history of the last 24 hours. It also monitors the indoor and outdoor temperature and humidity:

Includes Three Remote Sensors

The three included remote sensors start with the rain gauge, which shows the amount of rain (in mm or inches) that has fallen in the last hour or the last month. An anemometer measures average wind speed, direction and calculates the wind chill factor and dew point for you. It also gives details of moon phase and sunrise and sunset times, a feature that is particularly useful for golfers, gardeners and walkers. It’s measuring range for outdoor temperatures is from -40 to +80°C and for indoor -10 to +60°C, (reversible °C/°F) and humidity 1 to 99%.

The well built sensors can be positioned up to 100 metres away. The Sinus is supplied with one sensor included and can have up to four sensors positioned in different locations to give a range of readings.

Data Logger

The Sinus has a built in data logger which can store up to 200 climate records without using a computer connection but it also comes with computer software and a USB connection cable which allows you to connect the base to your PC and upload all the data that has been collected for record keeping and analysis.

It has a programmable alarm for certain conditions like temperature alarm, storm warning and a radio controlled clock with different alarms and a snooze function, which displays the date and weekday in a choice of six languages.

The clear digital display and LED back light make reading the information gathered easy. The attractive design means it looks good anywhere. The Sinus Wireless is perfect for anyone interested in accurate, up to the minute forecasts. For the latest prices visit Amazon.

Best Price For Sinus Wireless Weather Station is a post from: Weather Stations For Home

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We love the good looking Meteo Max Wireless Weather Station because of the easy to read displays of the outdoor temperature provided by up to three transmitters (max. 30 m),  the temperature tendency, indication of indoor temperature and humidity and max.-min.-function.  Weather forecasts are provided by symbols and Meteo Max (22 variations of clothes).  It also gives tendency of atmospheric pressure, absolute and relative atmospheric pressure with 12 hours history and bar graph indication.

It has a radio controlled clock with alarm and date and for keen golfers, gardeners and walkers it gives the time of rising and setting of sun and moon (146 European cities available) and an indication of moon phase.  The measuring range temperature for outdoor is  -50..+70° (-58..+158°F), and indoor 0..+50°C (+32..+122°F), reversible °C/°F, humidity 20..99 %.  The time zone can be varied ±12 hrs.  It is suitable for for hanging or standing and the high gloss piano-finish means it looks good anywhere in your home.  For the latest cost of this reasonably priced weather station go to Amazon.

equipment: outdoor temperature transmitter with optional sensor cable 30.3139,
batteries 3 x 1,5 V AA display station, 2 x 1,5 V AAA transmitter
230 x 150 x 33 mm, 95 x 65 x 25 mm, 800 g ….read more

Meteo Max Wireless Weather Station is a post from: Weather Stations For Home

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The all-in-one BAA898HG weather forecasting device from Oregon Scientific has multiple weather functions. The internal antenna gives this unit a reception range up to 100 metres. On its own, it monitors indoor temperature and humidity, but with up to three wireless remote thermo-hygro sensor it can monitor temperatures and humidities simultaneously, all in different 3 remote locations (one remote sensor is included).  The BAA898HG shows trends in temperature and humidity plus it records minimum and maximum humidity and temperature.  It does also provide weather forecasting, with a barometer displaying atmospheric pressure and kinetic graphics to show trends in atmospheric pressure as well as showing forecasts such as as sunny, partly cloudy, cloudy, rainy and snowy.

Technical Details

• Easy to read Barometer with weather forecasting symbols and current barometric pressure reading (hPa)
• Indoor/outdoor temperature and humidity
• Synchronises with up to 3 remote sensors (1 included)
• Temperature, pressure & humidity trend indicators, frost alarm and backlight
• Comfort level indicators, accurate radio-controlled clock with calendar & alarm with snooze….read more

Oregon Scientific BAA898HG Wireless InOut Thermo Hydrometer Weather Station is a post from: Weather Stations For Home

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monitor all weather information from your own home and plan ahead ….read more

weathereye weather station wea24 is a post from: Weather Stations For Home

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Item Weight: 100 g

Item Dimensions: 2.5 x .75 x 3.75 inches.

Build up your WMR90, WMR100 or WMR200 weather system with this additional THGR810 thermometer and humidity sensor. Designed by Oregon Scientific, this remote sensor monitors both temperature and humidity levels in a room with a high degree of precision. Typical maximum range is around thirty metres, but will vary depending on the materials between the unit and the base weather station (metal or bodies of water will reduce the maximum distance).

This highly rated auxiliary device is wireless and powered by two AAA batteries. The unit also features a local LCD display – useful for sanity checking the unit without needing to dismount it and take it to the base weather station. The unit has ten channels (just select using the CODE button), so you will be able to avoid channels that suffer local radio interference. The WMR810 also comes with a wall mount.

Please check sensor compatibility with your main unit before purchase.

As a bonus, here’s an inside the product view on how to modify the Oregon Scientific THGR 810 temperature/humidity sensor to a global radiation sensor (strictly at your own risk).

Cheapest Oregon Scientific THGR810 Thermometer & Humidity Sensor For WMR100 is a post from: Weather Stations For Home

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Browse more Oregon Scientific Weather Stations

The Oregon Scientific WMR88 Full Weather Station with USB Interface has only been available since October 2010. Since then it has taken the weather world by storm and established itself as a must-have weather station for keen home users.

This tremendous modern weather station for the home provides live localised weather information and a forecast more accurate than the general weather forecasts available from the media.

WMR88′s big bold display will provide you with temperature and humidity indoors and outdoors as well as rainfall, wind-speed and direction, and of course the forecast for upcoming weather. Barometric pressure is shown on bar graphs, and there’s even room on the display for current phase of the moon.

Wireless Sensors For Your Home Weather Station

One the many compelling reasons for selecting this particular weather station is the fact that all external sensors are wireless. This means no ugly mess of cables draped from your garden to a weather display inside. It also of course means that installation is far easier than with many other types of meteorological station. Each  external sensor communicates with the display unit via a radio link and with a hefty range of upto 330 feet it won’t restrict your options for a good location for those sensors. Establishing communications with the sensors is a simple matter of pressing a “search” button (just the same way that you set up a wireless keyboard).

The WMR88 is Also A Self-Adjusting Clock

The WMR88 also hosts a radio controlled clock for split-second accurate time for the UK and Europe. The central unit operates on either mains electricity or battery power – we’d recommend mains electricity for convenience, but if you cannot spare a socket or you take this to and from a holiday home, we found battery life quite reasonable.

Oregon Scientific WMR88 Bundled Remote Sensors

The Oregon Scientific WMR 88 comes bundled with the following three remote wireless sensors:

• Indoor/Outdoor Temperature & Humidity
• Wind speed, Wind direction and Wind chill
• Rain gauge

These can each be placed for optimal readings – the more spread the better (for more advice on sensor locations checkout our simple guide to choosing a good location). Each device relays its data automatically to the base unit for live readings as well as ongoing forecast. Note that it is possible to add an additional UV (ultra violet light) sensor – we discuss that sensor elsewhere, but for now it’s worth bearing in mind for adding sunlight-hours to the system’s forecasting data source.

Also included on the display are beautiful pictograms showing the forecast weather for the next 12 to 24 hours:

The forecast weather display

As well as displays of pressure trends and a lovely phase of the moon image.

In case you want to extend your use of your very personal weather data, the WMR88 has a USB interface which we found works well for transferring the juicy raw sensor reading data to your PC. You can juggle the data and form additional more detailed forecasts using your own forecasting techniques.

Shipping weight for the Oregon Scientific WMR88 Wireless Weather Station and three bundled sensors is 3.2kg. The entire set comes provided in full retail packaging, making it the ideal gift for the weather buff in your family. Take a look at the manual here.

The Oregon WMR88 comes with a full one year guarantee for peace of mind and in our view is a terrific choice as a mid-level weather station for home.

Oregon Scientific WMR88 Features

• Weather Forecast
• Indoor/Outdoor Temperature & Humidity
• Wind speed, Wind direction and Wind chill
• Rain gauge
• Max/Min temperature & humidity memory
• Dew point temperature Bar graph to show history of Barometric pressure, Rainfall and UVI (UV sensor not included)
• Upload data through USB port to PC
• Radio controlled clock
• Moon phase

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Precision’s PREC0046 is a solid main base plus sensor weather station in functional no-nonsense white plastic, iPod 2nd generation style.

It is some way up the mid-range for a weather station, offering four day weather forecasts covering sixty regions!  (you also get an additional 30 regions, but the forecast is a more modest two days for those). It achieves this clever trick by means of radio control where the weather forecast comes from Meteotime rather than raw on-board processing and number-crunching. the usual internal barometer and a simple calculation.

That radio signal from Meteotime includes weather information broadcast via stations in the same manner as radio-controlled clocks (which this is as well – no need to change the clock twice a year). Those broadcasts are not just meter readings, they are forecasts fully generated on METEOTIME, worked out daily by professional meterologists. There are no recurring charges.

You also get weather status for up to 272 European cities  belying its plain exterior.

The remote sensor gives teperature and humidity data to the main station wirelessly and you can mount it outside, ideally protected from the elements (it does not enjoy direct sunlight or rain).

What’s In The Box?

• Meteotime radio controlled weather forecaster

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The La Crosse WS868015 premium weather station benefits from a huge range of excellent features in an easy-to-read display. Ideal for anyone involved in marine activities as it measures barometric pressure and history in a graph display.

If you wish to measure the temperature in more than one place, you can use up to three TX4-868 temperature transmitters with the WS868015 (one transmitter included with station). You can look at the WS868015 manual here.

….read more

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The Lifemax electronic weather forecaster with radio controlled clock and weather information from the built in thermometer and remote sensor (one included). It has a large 30 cm analogue clock face with two LCD screens for both weather and temperature information.

Features :

* The first LCD display receives data back from the wireless remote sensor to record the outdoor temperature

* One remote sensor included and will operate up to two extra remote sensor units (available as an option)

* The second LCD display shows the indoor temperatures and humidity

* Clear graphics with weather trend icons

* Radio controlled clock provides split second accuracy

* Measures 30.5 x 4.1 x 30.5 cm

* Remote uses 2 x AAA batteries (not included)

* Main unit uses 3 x AA batteries (not included)

The Clock can use up to 3 remote sensors. 1 is included with the Clock. Additional sensors can be purchased from Amazon ….read more

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with dual channel transmitter for wireless transmission (max. 100 m) of outdoor temperature
and optional sensor cable,
one additional channel available,
indication of indoor temperature and indoor humidity, comfort level,
max.-min.-function, radio controlled clock, date,
measuring range temperature outdoor -40…+60°C (-40…+140°F), indoor 0…+60°C (+32…+140°F),
reversible °C/°F, humidity 1…99%,
time zone ±12 hrs, DCF-off-function,
for hanging or standing,

equipment: outdoor temperature transmitter 30.3143.IT, batteries 3 x 1.5 V AA display station, 2 x 1.5 V AAA transmitter
142 x 30 x 80 mm, 128 x 41 x 19 mm, 380 g ….read more

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We love the Oregon Scientific Solar Weather Station Advance BAR 808 because of the number of features it manages to pack into this neat little solar-powered unit and because of its clear easy to read LCD screen.  On the screen you will see clear displays of the weather forecast, radio control clock, calendar and the indoor and outdoor temperature with an indicator of the general weather trend.  It also gives you a moon phase display, indoor and outdoor humidity (again with an indicator of the trend) as well as a weather warning message and an ice alert. All these weather monitoring essentials make the Oregon Scientific Solar Weather Station Advance BAR 808 one of the best on the market particularly for the reasonable price.  For the up to the minute price on this product click here.

One of the best features of the Oregon Scientific BAR 808 Solar Weather Station Advance is the unit’s energy saving solar panel which is an environmentally friendly way of maximising the station’s battery life.  It manages to absorb and store power during daylight and then switches over to the batteries at night.   The unit can collect data from up to three sensors and set up is fast and simple.  All you have to do is place the remote sensor within 30 metres (98 ft) of the main unit.  You can use the table stand or the wall unit to do this.  The best place for the remote sensor is on the exterior of your home no higher than 5 feet, ideally away from direct sunlight or wet conditions to aid accurate reading.

The Oregon Scientific Solar Weather Station Advance BAR 808 forecasts the weather for the next 12 to 24 hours within a 30-35Km (19-21 mile) radius making it an essential item for anyone interested in the weather on a day to day basis. You can check out the manual here.

Product Features

Technical Details

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The newest Oregon Scientific 3 channel temperature sensor. It supersedes the older model THN122N. This replacement three channel temperature sensor is compatible with the following models: BAR206 BAR806 RMR332ES.

The Oregon Scientific THN132N can also be used for the following discontinued weather stations: BAR386 BAR626 BAR636 BAR686 RAR621 RAR681 RMR682 ….read more

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Wild Weather is a tremendously entertaining DVD from the BBC – a major documentary series of four one-hour episodes exploring the weather extremes around the world with dynamic presenter Donal MacIntyre.

Exactly as you would expect from the BBC, the quality of filming, CGI effects and music are top-notch and this has become one of the BBC’s great DVD successes.

Covering wind, wet, cold and heat and exploring the resultant hurricanes, monsoons, ice storms and tornadoes, Donal travels from beneath the North Pole to the Belise tropical rainforest.

The journey is thrilling and sometimes a little graphic – if your kids hide behind the sofa when Doctor Who comes on, you might want to quiten your telly before showing them this fine DVD series.

MacIntyre gets stuck in jumping out of a plane, receiving a battering in a wind tunnel, chilling out in an ice-box, feeling the force of a reservoir flood full on and pulling drearily through a Saharan marathon.

Good quality computer graphics are used to both provide clear technical explanations and to illustrate the meaty personal anecdotes of surviving victims of weather extremes.

So is it a geography lesson or a survival adventure?

It’s both, but educational in the best possible way – you will be wiser for the experience and it’s a very quick four hours.

Consistent with the best BBC documentaries, the BBC Wild Weather DVD is a good choice for you or a fellow weather-nut.

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This wireless weather station / clock with remote sensor provides accurate temperature readings for indoors and outdoors, includes a weather forecast feature, as well as an accurate humidity reading.

This revolutionary radio controlled clock designed by Thierry Mugler automatically synchronises with the local radio broadcast’s standard time so you don’t ever need to worry about checking for accuracy or making adjustments.

Rest assured you’ll be punctual for every appointment!

Features:

- Clock & Alarm

- snooze function on alarm

- Indoor and outdoor temperature (degrees or fahrenheit)

- weather trend indicator

- Date

- Outdoor humidity

- Weekday

- Moon Phase

- Battery indicator
….read more

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La Crosse Technology Projection Weather Station Plus

The La Crosse Projection Weather Station Plus positions itself handily between two markets: it’s way better than a budget-priced basic featureless model and a a weather station in the mid-range, which for some might be considered too much trouble to configure and use in your bedroom or kitchen.

Limitations and Ambitions from La Crosse

This model from La Crosse limits its ambitions in some ways and exceeds them in others. Presentation-wise, it sticks with the use of an LCD man to represent the upcoming weather conditions but it is the two main extra features which catch the eye:

• time projector - you can beam the time onto a wall or ceiling! Most purchasers will use this in the bedroom as the effect is most effective in a dark room. You might never use it after day one, but it is a little nugget of fun.

• wireless sensor – much more meaningfully in a weather station, laCrosse have succeeded in bundling a wireless sensor to be positioned outdoors. As we all know, this is essential for a weather forecast to have any meaning as centrally heated homes tend not to reflect atmospheric conditions at all well.

Recommendations for La Crosse

We recommend La Crosse’s Projection Station to those for whom a basic station is a joke but a mid-range station is too much effort.

Specification:-

Radio controlled time and date – Manual setting
Alarm clock – Snooze
Weather forecast
Indoor / Outdoor temperatures (°C or °F)
Indoor humidity (%RH)
Time and / or outdoor temperature wall projection
Delivered with AC/DC cable
CLOCK : L x W x H = 128.7 x 51.3 x 93mm
TX17 : L x W x H = 39 x 21 x 128mm

….read more

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The Davis Vantage Vue Weather Station delivers precise, reliable weather monitoring in a self-contained, easily installed system. It will provide all the weather information you require whether it’s for home, educational or boating use and more. Plastimo Auto Focus Binoculars give instant focus without having to play with a dial for a bright and sharp image. ….read more

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With the La Crosse Technology WS1501 weather station you can monitor the air quality as well as getting an accurate up to minute weather forecast.

The WS1501 weather station also features clock and calendar functions and uses an easy-to-read icon system to display its accurate weather forecast.

The WS1501 weather station even measures the wind speed and total precipitation over the last 24 hours.

Quartz Clock

Indoor/Outdoor Temperature (oC or oF) Precision: 0.10C

Outdoor humidities (%RH) Precision: 1% Accuracy: +/- 3%

Swiss Made High Definition Sensor

Rain Fall: mm or inch – 24hr

Wind direction and wind speed (km/h, m/s, knots,mph, or Beaufort)

Windchill display

Forecast Barometer with 3 icon display

Atmospheric Pressure (hPa or inHg)

Recording of Min/Max with time and date for all data measured

7 Alarm settings

LCD Contrast and LED Backlight

Stores and displays up to 140 sets of weather data.

Frequency: 868Mhz

Station: 170 x 32 x 139 mm

Includes transmitters shown in picture

….read more

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The Digital Window Thermometer is an extremely popular choice for anybody wanting an external thermometer reading without the flaff of owning and maintaining a full base station and remote wireless sensor.

Indeed, rather than take up space inside your house, this clever beggar sticks to the outside of your window – you look through the window to see what the temperature is. Nice.

General advice here would be that you ignore the instructions about sticking the holder section to the glass of your window and instead use the frame itself – this tends to hold the stuck on holder longer, through the travails of a UK winter. If the glue does lose its mojo, you can just use Sticky Fixers to remount it.

As you can see from the picture, the thermometer display is transparent – this is cool to look at until it gets dark outside – you cannot see the numbers unless there is a light source behind it.

Or you can do what others do and stick it on the inside of your window, but we feel that is kind of missing the point.

But what are you expecting for under fifteen quid?

As a fun thermometer that gives a more meaningful external rather than internal temperature, we like it.

It’s not a full weather station, but we rather like that it picks one task and writes it large: how warm is it now and how cold and warm has it been?

The Digital Window Thermometer is a fun gift and you can safely give it to someone who doesn’t read instructions.

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We love the Smart Weather Wireless weather station with remote sensor (100m range) because it provides accurate temperature readings for indoors and outdoors. It has loads of other features including a weather forecaster based on barometer readings which allows you to plan your activities according to the weather.  This is great for anyone interested in outdoor pursuits such as gardening, golfing and walking.  The Smart Weather will also store your record high and low temperatures, and features an alarm, calender and clock.   We think this is a  great weather station for anyone interested in monitoring the ever changing British weather.  For the very latest price go to Amazon.

Features:

1) Indoor humidity (% RH)
2) Wireless outdoor and indoor temperature (F or C)
3) Records min. And max. Humidity
4) Records min. And max. Temperature
5) Weather forecast tendency arrow
6) Weather Forecast icons based on changing barometric pressure
7) Radio Controlled Time and date with manual setting
Time Zone Setting
9) 12 or 24-hour time display
10) Perpetual calendar
11) Time alarm
12) Storm Alarm
13) Can receive up to 3 sensors
14) LED backlight
15) Wall hanging or free standing
16) Included transmitter WH3
17) Synchronized instant reception
18) 2 years battery life
19) Low battery indicator on the receiver

Specification:

1) Indoor humidity range: 20% to 99%
2) Wireless outdoor temperature range: -40 C to 65 C
3) Indoor temperature range: -9. 9 C to 80 C
4) Temperature accuracy / 1 1. 0 C
5) Transmission range: up to 100 meter (330 feet)
6) Transmission frequency: 433MHz

Power Requirements:

1) Receiver: 2 x AA alkaline batteries
2) Wireless sensor: 2 x AAA alkaline batteries

Dimensions: (HxLXW)

1) Receiver: 145x82x26mm
2) Sensor: 91x70x32. 5mm ….read more

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With the UVN 800 wireless sensor from Oregon Scientific, you can monitor the levels of ultra-violet light over the last ten hours. – Compatible with 3.0 weather stations – Transmission frequency: 433 MHz – Transmission distance: 100 metres – Can be wall mounted or installed on a post planted in the ground – Power: 2 x LR06 ….read more

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This THWR800 wireless floating temperature sensor is designed by Oregon Scientific for professional weather stations. You can use it in the pool, hot tub, boat, lake or anywhere you want to know the temperature of the water. This sensor lets you monitor the temperature of water using wireless technology and a floating system. Its casing is UV-resistant and waterproof, and the sensor itself has a transmission range of 100 metres. ….read more

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The BA900 from Oregon Scientific looks like a giant chunk of crystal and is quite different to any weather station we’ve ever seen. Yes, it is a proper weather station, but not as we know it. The 3D icons display the forecast weather, which is augmented with projecting lights in different colours, red for sunny, blue for cloudy and green for rain. This clever arrangement means you can “read” the weather from across the room. The Crystal Weather Station is almost more like modern art than a scientific instrument – it’s a combination of both. The BA90o0 is mains powered and does not take batteries, the upshot being that the Crystal is intended for indoor display and should almost be considered as a piece of furniture. Certainly, the very bright display makes it unsuitable for a bedroom unless you like to sleep to swirls of colour.

You can grab the BA900 Crystal Weather Station manual here.

• First weather station in the world to incorporate laser engraving of  3D icons within the crystal
• Coloured light illuminates the 3D icon weather forecast
• Clock is radio-controlled for accuracy and convenience
• The Crystal Weather Stataion can detect hand motions, which change the display mode between time and indoor temperature
• Animated display, easy to…read more

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shape: square, crystal: synthetic crystal, Case: synthetic, face: orange, display: digital display, digits: arabic, drive: solar, radiocontrolled: radiocontrolled ….read more

You can read our review of the Oregon Scientific BAR 808 here.

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A fun little weather station that takes its design cues from those large dinosaur classic American cars of the 1950s. Think American Graffiti rather than Logan’s Run. Intended to be redolent of gazing at a curvy dashboard with the wind in your hair. A gift for retro fans (or someone that already has three weather stations…).

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Home weather fans want a combination of features, practicality and price from our weather monitoring gear. Do you get significantly more features as you climb the scale from quality budget model to mid-range gem? For our investigations, we chose to compare the budget-priced classic Oregon Scientific BAR208 against the mighty Teutonic Nexus Wireless.

So which weather station is better – there’s only one way to find out! Fight!

The Oregon Scientific BAR208 Wireless Weather Station

Product Features:

• Indoor / Outdoor Temperature and Humidity
• Weather Forecast
• Weather Warning Message
• Radio Controlled Clock Reception
• Ice Alert!

• Indoor & Outdoor temperature and humidity measurement with trend
• Weather forecast with pressure trend Weather warning message
• Ice Alert with Green LED blinking indication
• Radio-controlled clock with calendar
• Product Dimensions 183 x 45 x 92 (hxwxl)mm

Technical Details

• Indoor temperature and humidity with trend
• Outdoor temperature and humidity with trend
• THGN132N Remote Sensor
• Max and min for temperature and humidity readings
• Weather forecast with pressure trend
• Ice Alert with Green LED blinking indication
• Weather warning message: Heat/Fog/Frost/Storm/Wind
• Moon Phases
• Radio-controlled clock with calendar from MSF in UK or DCF in Germany
• LED backlight
• Table Standing

Average Customer Review: 4 stars out of 5 (19 customer reviews)

versus

The Nexus Wireless Weather Station

Technical Details

• indoor and outdoor temperature
• huimidity and rainfall quantity
• weather forecast and storm warning
• windchill factor
• radio controlled clock

Product Description

Transmission of outdoor values wireless (max. 100 m), display of outdoor temperature and humidity, rainfall quantity, wind velocity and direction, indoor temperature and humidity with comfort level indicator, absolute and relative atmospheric pressure with 24 hours history, weather forecast and tendency of atmospheric pressure, bar graph indication of atmospheric pressure, temperature or humidity for the last 24 hours, calculation of Windchill factor and dew point, max.-min.-function, programmable alarm functions for certain weather conditions like temperature alarm, storm warning, radio controlled clock with different alarms and snooze function, display of date and weekday (6 languages), time of sun rising and setting, indication of moon phase, data memory for 3000 weather records, PC- Interface with analysis software package, LED Backlight with light sensor (in continuous operation with power adapter, including UK-adapter), measuring range temperature outdoor -40…+80°C (-40…+176°F), indoor -10…+60°C (14…+140°F), reversible °C/°F, humidity 1…99%, for hanging or standing, equipment: thermo-hygro-sensor, wind sensor, rain sensor, CD-ROM (English/German), USB cable, power adapter 7.5 V AC/DC (german version, adapter needed), batteries 4 x 1,5 V AA display station, 2 x 1,5 V AA thermo-hygro-sensor, 2 x 1.5 V AA wind sensor, 2 x 1.5 V AA rain sensor, expandable up to 5 thermo-hygro-sensors 30.3150 220 x 165 x 32 mm, 2670

Average Customer Review 4.5 stars out of 5 (11 customer reviews)

Our Conclusion

Both of these weather stations are popular and above average in terms of features offered and value for money. Ultimately, the Nexus has a stronger feature set and is worth the money if your budget can stretch to over £150. If you are on a tighter budget, the BAR208 is only slightly less able but with a street price of under £50 here if you are quick. Pound for pound, the WeatherStationsForHome Seal Of Approval (honk honk!) goes to the Oregon Scientific BAR208 Wireless Weather Station.

WSH

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Oregon Scientific’s WMR88 Pro Weather Station is a step up from other mid-range weather stations.

The kit comes with everything you need to get serious about meteorology and =home weather monitoring. Just add a PC, batteries and some enthusiasm.

WMR 88 Pro comes with three remote wireless sensors providing air pressure, rainfall and wind speed data – the classic elements of a weather forecast.

WMR88 sensor pack

The WMR80 includes a thermo-hygrometer – this is a device that measures air temperature and humidity, both inside and outdoors.

As you would expect with a premium domestic station, you also get some extra features -such as lunar phase display, heat index and dew point.

The sensorts have a line of sight range of 100 m, but count on that distance falling off sharply as you introduce shed walls into the reckoning.

Our earlier reference to a PC is for the Oregon Scientific WMR88 Pro’s ability to share its data with your PC via the provided USB connection.

That  allows you to play with the data and really get down and dirty with the stuff of weather forecasting (or you can just leave the cable in the box!)

The WMR88 Pro can run on batteries or be mains-powered (our reommended choice), while the outdoor sensors require infrequent battery changes (LEDs will indicate low-power) and the WMR80 will also warn you of loss of signal.

A good choice for those serious about forecasting and toying with the idea of manipulating the raw data for home-brew forecasting.

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The THGR 228N from Oregon Scientific is a remote sensor, focused on its dual role as a thermo/hygrometer – this measures both the ambient temperature and humidity.

It can be used as a standalone device, as it has an integral LCD display, but is also suitable as an add-on remote sensor for a range of Oregon Scientific’s more advanced weather stations.

The THR228N  provides temperature readings over -20°C to +60°C with detailed humidity readings to a precision of 25% to 95%.

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Acctim’s very cheap Akero Weather Station really is remarkable value for money. For under fifteen pounds, you get a competent travel alarm clock that is also capable of predicting the weather for the next twelve hours. You get more sophistication than you would expect at this entry-level price, with the attractive chunky inverted digital read-out and the colourful weather display with animated icons depicting the weather ahead (sunny, bit cloudy, cloudy, going to rain).

You get maximum and minimum temperature (which alone justifies the price) but amazingly they also pack in humidity and temperature trend.

You’ll need two AAA batteries (which price does not include), or you can use the mains adaptor which does come in the box.

To give you an idea of size, the Acctim Weather Station is 65 x 130 x 22 mm.

Next time someone says there is no such thing as an ultra-cheap weather station, tell them about Acctim’s Akero.

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Some thoughts on the Smart Effects Technoline WS9130 weather station and remote sensor if you are considering buying one.  It sells at a budget price, especially for a weather station which comes complete with outdoor sensor. This is a lot less than some of our other more complicated stations, so you can expect to lose a couple of the more advanced features present in its big brothers and sisters. But for beginners, at this price-point you can afford to experiment, explore forecasting your local weather and learn a little about weather patterns.

The basic display shows clock, temperature and pressure direction (falling or rising). You do get weather forecasting – sunny, cloudy or wet is your lot, but it does this well. Try it and see. The clock is radio-controlled, so will become your home time reference for setting all your other clocks and watches and you won’t have to change the time every time the clocks go forward or backward.

One popular use for this station is among greenhouse owners - this device is perfect for remote monitoring of temperature in your greenhouse. You can set up minimum and maximum temperature alarms to keep control of the temperature range without opening the door of your greenhouse or even leaving your house. Now instead of marching out in all-weathers, you can have a quick glance at the WS9130 for an update on the greenhouse conditions.

Note that the remote sensor does not have an LCD read-out (not at this price), but it does have an LED to confirm communications with the base unit and to indicate low battery conditions.

Another omission to keep the price rock-bottom is that it does not come with batteries, so stock up on your AAs and AAAs when purchasing this terrific budget weather station….read more

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The Oregon Scientific BAR206 weather station comes with a very clear screen, providing providing weather forecasts looking ahead twelve to twenty four hours. An in-built barometer enables it to provide good local forecasts for your location. An outdoor sensor (which is wireless and battery operated) is also included with the package and provides the main unit with external temperatures to be processed alongside the indoors temperature monitored directly by the main base unit.

Up to three remote sensors can be used in total, so you can upgrade from the single external thermometer supplied. The range of the sensors is around 30m depending on conditions and battery level. We recommend long-life alkaline batteries rather than rechargeables.

The BAR206 also features a clock and calendar, while the weather forecast is displayed using simple icons.

The clock has the special benefit of keeping radio-controlled time, so no adjustment is required when the clocks go backward or forward. An alarm feature is available and is probably most useful when the BAR206 is used in a bedroom.

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