Station placement contradiction

[jferristx]

Ok, I've placed my station approximately 10 feet off the ground, with nothing closer than 50 feet to it. Sounds good so far, right? Well, my station reported a low temp of 36F, but I had frozen plants in my garden. So, next nite, same thing, except I put a min/max in the garden on the edge of a raised bed (6 inches off the ground). Station read 36, min/max read 32.

So.....how do I deal with this. Do I just adjust mentally? The distance from top of tower to where the temp needs to be taken is nearly 50 feet. If I put the station lower, weather and water readings will be affected.

Should I consider drinking decaf....

[beteljuice]

10 feet off the ground,

It should be approx. 4 ft 6in from the ground (approx. 'old' head height')

'Grass' temperatures should be lower (at night) than air temperature by a few degrees.

[wd40]

I had my unit up higher and as already posted, my temperatures did not match up till I lowered it. I assume too your unit is over grass, not a solid surface like concrete.

[beteljuice]

I assume too your unit is over grass,

In an ideal world it SHOULD be over grass

[jferristx]

Where is this ideal world? I'd like to go there.

I'm structure limited in terms of placement. I can lower it, though not to the 4' 6" mark (where did you get that reference BTW). I'm not over grass because this is Texas in the middle of it's worst drought in history, there is no such thing as grass left around here. I have an acre of ground, and the station is effectively in the middle of it. The land slopes about 20 feet in height from west side down to east side, so my location is in the middle for distance and slope. As "average" of spot as I could make it. I'm growing things in most locations on the property, either crops or fruit trees. I think I am going to have to do a basic temperature map of different places since taking the temp from one place isn't going to give me reliable enough readings for every place I need to measure it. I'll take my min/max and set it in different places and compare it to what the fix station says. I don't care about heat differences, hot is hot. But frost/freeze is not good.

Thanks

[Graham64]

There is some useful information on weather recording on the UK Met Office website and in particular in factsheet 17 at http://www.metoffice.gov.uk/media/pdf/k ... No._17.pdf. Amongst many other things, the factsheet refers to the different positions of temperature measurements and suggests that the grass surface can be artificial.

Is there anyone on this forum who has their weather station sited according to all these requirements? Mine definitely isn't!

Factsheet 17 has been referred to in previous topics on this forum.

[beteljuice]

[geoffp]

I am afraid that if I were to lower my temperature sensor to the recommended height I may start getting more problems then with the transmitting and receiving

[wd40]

jferristx, I too grow fruit trees here in South Ga. Our drought is getting bad too. Note Cumulus tracks chill hours.

I have citrus and apple trees. What are you growing?

[jtrost]

There are many, varying requirements for weather data, so you will likely find that one size does not fit all. I worked half my career in aviation weather and the other half in forestry weather. The needs of the two are vastly different. So, I suggest you consider what is most important for you. If your main concern is the garden, put the temperature sensor where it will most represent what is going on there. If your desire is to provide "standard" weather observations to supplement national weather networks, then try to duplicate their siting. You may even find that you need two temperature sensors at different heights to satisfy your needs. But you want your station to be representative. In other words if you live in west Texas, don't put the sensors near the swimming pool where humidity will be grossly out of whack. Don't put the temperature sensor near the dryer vent or air conditioner. Try to get the wind sensors away from anything that will shadow the true wind or induce turbulence. All in all a difficult task at best.

[Matt.j5b]

Hi
Just to add, I am in a suburban environment, and to get accurate readings I could not achieve this at one location. Instead I use 2 sensors and combine the min and max figures using the correct ones to close to ideal min and max figures for each day. One sensor reads too mild by night as its too protected but is correct during the day, with the other sensor more exposed on the north side of the house and reads overnight figures better but wrong for daytime with the heat of day ( with too high temp). For me that solves the problem siting my sensor in a good spot. I don't have any trouble siting my wind sensor and rain sensor on the top of a greenhouse as its virtually at the roofline and almost unobstructed from good airflow.

[hectic]

This is a hard one.
My garden is about 80 feet long and from the top of the garden to the bottom i get a temperature difference of approx 0.7 celcius. Sometimes the measurements are the same.
Now the temp gauge at the bottom of the garden always seems to be pretty accurate when it comes to frosts and comparing with other stations locally. Both sensors are the same hight as each other and both are over grass. So i am guessing that my garden has its own micro climate. I personally think that in general most of our readings are accurate to the positioning of our gauges but will never always be the same as the met office or other places because of the micro climates we have in various degrees around our stations.
I believe that your sensor should be approx 1200mm above the ground , which is about four feet.

[Matt.j5b]

Hi
You will generally get frost in hollows and low spots where the temperature is lower. Your microclimate would affect the readings if not just a open area. As you said the sensor should be 1.2 m and over grass.