Locating Outside Sensors.

[Zenarcher]

Thought I would make a quick quide for where your outdoor sensors for your weather station should be.

Temperature:

Should be placed at least 4ft above ground level. Ground level or soil temperatures should be measured with separate sensors if possible. It should also be avoided by sunlight and rainfall. Make sure it is in a position where free circulation of air can occur. Stuff like brick walls or concrete can make data not accurate.

Humidity:

Same situation with the temperature sensors but make sure its at beside the temperature sensor.

Wind speed and direction:

Try and make sure it is above 10m above ground level best to put it on a shed roof or on your house roof. The direction the obvious advice is to aim for maximum exposure of the anemometer. If you put it on a roof make sure its off the structure by 3m to 4m to get accurate data. If you have it on the roof structure it can cause errors and unaccurate readings.

Rainfall:

Make sure it is put in a very open area try to get as far away as any objects like a house and place it in a flat location, the reason for this is the wind can cause air turbulence and it makes the rain not reach it.

Pressure:

You will probably have this inside and it doesn't really matter where you put it but make sure the room its in doesn't get to hot.

Hope this helps .

Edited November 6, 2008 by weathermaster

[Louby]

Ok, so my temp sensor would be ok hanging from the ceiling of an old outside loo ? it has no window at the top so air can move freely and no sun light gets in at all.

[Zenarcher]

Ok, so my temp sensor would be ok hanging from the ceiling of an old outside loo ? it has no window at the top so air can move freely and no sun light gets in at all.

It should be depends if its on brick wall or concrete.

[Louby]

It should be depends if its on brick wall or concrete.

It's brick walls, with quite a few holes in them

[Zenarcher]

It's brick walls, with quite a few holes in them

Its sources of heat such as buildings and brick walls can make a slight change.

[Backtrack]

Weathermaster, Is my sensor ok here?  It had bamboo fence so air can get through i think

Also on the last picture can someone tell me what the bars mean please? They move up and down.(im guessing something to do with pressure)

SS

[I remember Atlantic 252]

mine is on an eastern facing fence (sheltered by house) 0ct-mid march, 2m from ground sun gets nowhere near it, i feel its accurate for mid 0ct to mid march

mid mar to early 0ct, this place inaccurate due to sun radiation on western side of fence off high sun angle from 4pm, although not in direct sunlight, so has to go on wall under a bush around 2 inches from ground, 0nly sun free place in summer

[Louby]

Its sources of heat such as buildings and brick walls can make a slight change.

So not too bad a place then, all I got to do is get it working again now or get another one Thanks for that WM

[Zenarcher]

Weathermaster, Is my sensor ok here? It had bamboo fence so air can get through i think

Also on the last picture can someone tell me what the bars mean please? They move up and down.(im guessing something to do with pressure)

SS

Its sitting on bricks so that will increase the heat move it away from bricks and concrete.

The bars show the pressure history.

So not too bad a place then, all I got to do is get it working again now or get another one Thanks for that WM :o

Hope you get it working.

[I remember Atlantic 252]

mine is on an eastern facing totally sheltered fence all this december, around 5 feet off the ground, it seems to give temps too high, 14.4oC max today, and ive had slippy paths and iced over pools with it on 2-3oC

should i move it to near ground level? again totally sheltered but more open

[Zenarcher]

mine is on an eastern facing totally sheltered fence all this december, around 5 feet off the ground, it seems to give temps too high, 14.4oC max today, and ive had slippy paths and iced over pools with it on 2-3oC

should i move it to near ground level? again totally sheltered but more open

Maybe lower it to 4ft above ground level but also make sure it is out of the sun at all times and fresh air is getting around it.

[weather1967]

I know for correct temperature must to use Stevenson screen box with wood, or Radiation shield with fan from plastic dishes . 1,5 - 2 meters over from ground

Edited December 18, 2008 by weather1967

[Terminal Moraine]

I know for correct temperature must to use Stevenson screen box with wood, or Radiation shield with fan from plastic dishes . 1,5 - 2 meters over from ground

I'll second that. There is no substitute for using either a Stevenson Screen or a radiation shield if you want to record reasonably accurate temperatures.

Any sensor or thermometer must have free air around it, never be subject to direct solar radiation and as little as possible to secondary solar radiation and should be sited about 4 feet above the ground in as open an area as possible.

If your sensor or thermometer is mounted on a fence or a wall there will be, at best a small amount of secondary radiation, and at worst a direct reading of the temperature of the fence or wall rather than that of the air. This will obviously be most noticeable when the sun is at its highest but even at this time of year the sun shining on one side of a fence, when your thermometer is mounted on the opposite side, will have a significant impact on the recorded temperature.

The same criteria are equally important at night for, although there is no sun, any sort of shelter, particularly from above, will result in reduced radiative cooling and the recording of higher temperatures than out in the open in an unobstructed area.

[The watcher]

Weathermaster, Is my sensor ok here? It had bamboo fence so air can get through i think

Also on the last picture can someone tell me what the bars mean please? They move up and down.(im guessing something to do with pressure)

SS

I have the Super Weather Station too lol. I set my sensor somewhere dry with full rain protection but with the wind able to get at it from all directions.

The bars indicate inHg (you can see the reading on left) which is inches of mercury, its a formula used to calculate the change in pressure by how mercury expands and shrinks (ie +0.06 inches = +2hPa. The readings on the opposite side depict hPa (Hectopascals), which is basically pressure. The bars therefore show the pattern in which Pressure has changed in the last 12 hours.

I think thats as best a description I can give you, I'm almost sure its correct but having only researched it myself Iam not 100% sure.

Edited December 29, 2008 by The watcher

[I remember Atlantic 252]

got a new thermometer from argos today, other one was knackered completely lost signal, and did seem to be registering too high wherever i put the sensor 15.6oC on 21st dec

my new one is a lexibook meteo clock, current temp 2.9oC

Edited January 18, 2009 by mark forster 630

[Icer]

Is beside a wooden shed fine? On the ground?