Oregon Scientific Wmr100na

[Snowstorm1]

I have problems with the temperature issue with this station it has calmed down as I kind have have protected it from the sun but still have problems with it any ideas?

Generally it is from 1degree - 3 degrees out but when it rained today heavily it gave a more realistic reading?

Ill post a picture tomorrow so you'se will have a better idea of its positioning/what's covering it properly

[Backtrack]

You need a stevenson screen. Although this won't protect it from direct sunlight as I have found out myself.

[Snowstorm1]

You need a stevenson screen. Although this won't protect it from direct sunlight as I have found out myself.

Were do you buy them from and how much am I looking at here and are they easy to put on?

[reef]

When you say 1-3 degrees out, what are you comparing it to?

If I remember rightly you suggested in the past that it was quite difficult to site as you only have a small yard and are very urban. If so, then your readings will very likely be quite different to a station in open grounds even if fully shielded.

The standard shield on the WMR100 is pretty poor (similar to the old LaCrosse WS2300 I used to run), if anything its mainly to stop the rain rather than shield from solar/reflected radiation. It'd definitely be worth investing in a screen of some sort (I found it made a big difference to maxima on that station). However it may be that your readings are pretty accurate for where you are and that you're just suffering from microclimatic factors.

[Snowstorm1]

When you say 1-3 degrees out, what are you comparing it to?

If I remember rightly you suggested in the past that it was quite difficult to site as you only have a small yard and are very urban. If so, then your readings will very likely be quite different to a station in open grounds even if fully shielded.

The standard shield on the WMR100 is pretty poor (similar to the old LaCrosse WS2300 I used to run), if anything its mainly to stop the rain rather than shield from solar/reflected radiation. It'd definitely be worth investing in a screen of some sort (I found it made a big difference to maxima on that station). However it may be that your readings are pretty accurate for where you are and that you're just suffering from microclimatic factors.

All the stations nearby http://www.wundergro...w:00000.1.03263 but this station in winter is normally about the same as mine http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=ISTOCKTO2 Ill post pictures tommorrow which will give a clearer idea

Edited August 4, 2011 by Snowstorm1

[Snowstorm1]

Its went 5Degrees out this morning because the sun was on a low angle enough to get to it here are some pictures so you'se can see what Im dealing with

[4wd]

I'm running an additional outdoor sensor literally at the shaded back door just because it's easy to glance at it when going in and out - it often reads 2 or 3 C higher than the Vue out at the end of the garden and it isn't in sun - just near the stone building which retains heat remarkably well.

Your best option might be to get the whole thing up higher if possible, it's the proximity to the sun-heated yard walls and floor which is your main problem.

You could just live with it on the understanding it's essentially an urban location which is interesting in itself as a comparison.

[Snowstorm1]

I'm running an additional outdoor sensor literally at the shaded back door just because it's easy to glance at it when going in and out - it often reads 2 or 3 C higher than the Vue out at the end of the garden and it isn't in sun - just near the stone building which retains heat remarkably well.

Your best option might be to get the whole thing up higher if possible, it's the proximity to the sun-heated yard walls and floor which is your main problem.

You could just live with it on the understanding it's essentially an urban location which is interesting in itself as a comparison.

I sound dum here but couldn't understand much of that! :')

[reef]

Looking at your pictures you're never going to get anywhere near that Teeside site for many reasons. The main ones are that your garden is almost completely concrete, which retains heat rather well. The other reason is its rather cramped, so it'll be be getting less airflow than is ideal. Honestly I agree with 4wd above and would try to get it higher (if anything so your anemometer is more exposed), though you'll have to accept you're never going to get readings that match a station in an open area with lots of shielding and airflow.

[Snowstorm1]

Looking at your pictures you're never going to get anywhere near that Teeside site for many reasons. The main ones are that your garden is almost completely concrete, which retains heat rather well. The other reason is its rather cramped, so it'll be be getting less airflow than is ideal. Honestly I agree with 4wd above and would try to get it higher (if anything so your anemometer is more exposed), though you'll have to accept you're never going to get readings that match a station in an open area with lots of shielding and airflow.

I cant get it higher sadly but the shield idea I'm very interested in!

Anyone can give any details were to buy from ?

How Much to cost?

Which one is the best for my weather station?

Any ideas will be much appreciated

[reef]

You would want something like this, though its out of stock at present:

http://www.weathershop.co.uk/shop/accessories/installation-kit/russellscientific-1292k-simple.html

[Snowstorm1]

You would want something like this, though its out of stock at present:

http://www.weathersh...92k-simple.html

Would that go in the middle of the yard like and go on a table (id have to have one for it or something comes with it) and would it fix most my temp worries with it?

Also would I just put the temperature sensor in there and leave the wind and rain gauge outside?

Bit expensive so would take a while till i get my college money coming through in September Id be able to get it but that's fine

[reef]

Would that go in the middle of the yard like and go on a table (id have to have one for it or something comes with it) and would it fix most my temp worries with it?

Also would I just put the temperature sensor in there and leave the wind and rain gauge outside?

Bit expensive so would take a while till i get my college money coming through in September Id be able to get it but that's fine

It says it can be post or wall-mounted, so you can put it where you like. You only want your temperature sensor in there, the wind and rain gauge stay outside.

You should be aware though that even with perfect shielding you're never going to get the temperatures of a well ventilated and open site. Higher maxima and lower minima will be the likely result due to urban heat island effects.

[Snowstorm1]

It says it can be post or wall-mounted, so you can put it where you like. You only want your temperature sensor in there, the wind and rain gauge stay outside.

You should be aware though that even with perfect shielding you're never going to get the temperatures of a well ventilated and open site. Higher maxima and lower minima will be the likely result due to urban heat island effects.

That is cool and at the minuite the temp is always higher day or night which is weird it is such a nightmare aha all the problems I have had with it

[reef]

That is cool and at the minuite the temp is always higher day or night which is weird it is such a nightmare aha all the problems I have had with it

A bit of a brainfart there, I actually meant higher maxima and minima!

[Snowstorm1]

A bit of a brainfart there, I actually meant higher maxima and minima!

Great how come in winter it isn't too bad but in summer goes way off what it should be like now its 3c off what it should be?

Id just be happy for it to come into line with other areas nearby so it had credibility but it been out few degrees most the time is really annoying me

At first I thought the heat coming from the house may have something to do with it so I moved it onto the other wall but little change has happened

[Nights King]

Great how come in winter it isn't too bad but in summer goes way off what it should be like now its 3c off what it should be?

Id just be happy for it to come into line with other areas nearby so it had credibility but it been out few degrees most the time is really annoying me

At first I thought the heat coming from the house may have something to do with it so I moved it onto the other wall but little change has happened

Strange you have mentioned this because I have just installed the same station and I am constantly reading around 1-3c warmer than another local station at the same altitude and rural location. I think it needs better shielding, another way of checking would be to have a look and see if the humidity is always less than other stations?

[Snowstorm1]

Strange you have mentioned this because I have just installed the same station and I am constantly reading around 1-3c warmer than another local station at the same altitude and rural location. I think it needs better shielding, another way of checking would be to have a look and see if the humidity is always less than other stations?

Yes it is lower mate most the time however it wouldn't explain the difference fully

Edited August 6, 2011 by Snowstorm1

[Nights King]

Yes it is lower mate most the time however it wouldn't explain the difference fully

Yes mine is currently reading 14c when it should be around the 12c mark but I can tell its being afected by solar influence because humidity is only reading 74% unlike others which are all in the 90's

[Snowstorm1]

Yes mine is currently reading 14c when it should be around the 12c mark but I can tell its being afected by solar influence because humidity is only reading 74% unlike others which are all in the 90's

Mine is reading 89% when others are 93%+ in my area actually that seems preety okay that doesnt it?

Ive literally just dont know what to do with it when i know for a fact its wrong ive just lost all ideas that screen one seemed okay till the reply was it may not work completely but id just be happy for it to achieve correct constantish readings

[Nights King]

Mine is reading 89% when others are 93%+ in my area actually that seems preety okay that doesnt it?

Ive literally just dont know what to do with it when i know for a fact its wrong ive just lost all ideas that screen one seemed okay till the reply was it may not work completely but id just be happy for it to achieve correct constantish readings

If your reading is all ways a constant 1/2/3c off what it should be and you are sure of that then maybe its worth calibrating your weather software to adjust temperature down -1c/-2c?

[Snowstorm1]

If your reading is all ways a constant 1/2/3c off what it should be and you are sure of that then maybe its worth calibrating your weather software to adjust temperature down -1c/-2c?

Its not only that though it varies between 1c to 3c but when it rains heavily it can get to around the right temp but as soon as it stops it goes back up also and when the sun is on it can go 6c out but in winter it does give better readings

Ive adjusted temp down by 1 degree and humidity increased by 4% see how this works now

Edited August 6, 2011 by Snowstorm1

[reef]

The humidity sensor in the WMR100 is notoriously poor. Its peak range is 40-80% where it is accurate to +/- 5%. Below 40% and above 80% that accuracy decreases to +/-7%! Essentially this means that you could be reading 86% when an 'official' station is reading 93% and it'd still be within specification.

The reason your temperatures are more accurate during the daytime when its raining and during winter is because at those times solar radiation is at a minimum. You can set an offset (temperature adjust) but then you'll under-read during the night.

I think you'll probably just have to shield it the best you can and accept its in an environment thats slightly warmer than other stations elsewhere.

[Snowstorm1]

The humidity sensor in the WMR100 is notoriously poor. Its peak range is 40-80% where it is accurate to +/- 5%. Below 40% and above 80% that accuracy decreases to +/-7%! Essentially this means that you could be reading 86% when an 'official' station is reading 93% and it'd still be within specification.

The reason your temperatures are more accurate during the daytime when its raining and during winter is because at those times solar radiation is at a minimum. You can set an offset (temperature adjust) but then you'll under-read during the night.

I think you'll probably just have to shield it the best you can and accept its in an environment thats slightly warmer than other stations elsewhere.

Oh right is putting the temperature down by 1 degree and humidity up by 4% can help my problem during spring/summer/autumn?

Then maybe in winter half that so its only decreased by 0.5c and 2% and what months would you suggest to do this in winter when solar radiation is at minimum?

[reef]

Oh right is putting the temperature down by 1 degree and humidity up by 4% can help my problem during spring/summer/autumn?

Then maybe in winter half that so its only decreased by 0.5c and 2% and what months would you suggest to do this in winter when solar radiation is at minimum?

I wouldnt change the temperature 'live' in your software, but rather do an adjustment in your records if its been a sunny day. So for example on a very sunny day if you had a max temp of 24C and min of 12C, take 2C off when you record the temperature (so 22C/12C). On the other hand, if its been overcast and had a max of 18C with little solar radiation, then leave it be. Its very crude though, I wouldnt really recommend it. Humidity is a tricky beast, Id be tempted to leave it be. The problem with a blanket adjustment is that your sensor might not necessarily be out by the same amount throughout its range. You could end up pushing it even further out quite easily. Plus if you're so determined to have your results match other sites then it sort of defeats the point of having your own station.

At the end of the day though you're recording the temperature in your garden which is actually warmer than sites nearby. No amount of tinkering will change that fact unfortunately. Id concentrate on finding the absolute best location for the sensor and shield it as best as possible from solar radiation. Most of us have to do this, unless you're lucky enough to have a massive garden that is!