Post a Pic of Your Weather Station

I was starting to worry I might have serious issues with radiation shielding on my station, because the last few sunny days my station has recorded highs multiple degrees warmer than the airport, and even up to a degree warmer than the Uni station. Today my station recorded 17.3'C, while the Uni station only recorded 16.3'C, and the PWS just west of Umeå's border only recorded a high of 15.6'C. The warmest hourly reading at the airport has been below 15'C too.

This is the current placement of the station. I moved it slightly so that I'd have a clear line of sight from my balcony. As you can see it's about 8 meters away from the road, and pretty near some (bare) bushes (the tall bushes look like they're closer to the station than the actual 2-3 meters). It's also about 1.5 m high which is within the WMO standard but lower than the more typical 2.0 m.


I checked with a grill thermometer and when placing the thermometer right underneat the station (in its shade), the thermometer would read about the same or warmer, and when I inserted the thermometer probe inside the radiation shield it would read the same or slightly lower. Of note is that the temperature could easily vary by a whole degree within a 50 meter area when I walked around with the thermometer in the shade generated by my own body. And as soon as there was a gust of wind, the temps could drop by up to 2 degrees.

My conclusion is that there is a vast difference between the temperature >5m up in the air, and the air closer to the ground, and any wind mixing the air will dramatically decrease the 1.5-2m temps. Likewise, areas with dry grass or leafy ground will be substantially warmer than places just a dozen meters away with wet ground from nearby snow piles or recent snowcover. Winds could be absolutely non-existant for quite long periods of time, allowing hot thermals from dry ground to rise and increase 1.5-2m temps really dramatically. Thus I actually do trust the readings from my PWS. However, as I biked around the area (holding the meat thermometer), I did notice that most places were a degree cooler than the particular spot where my station is placed, either because of more recent snow cover or, counterintuitively, because of too many houses nearby. I noticed the more densely built neighborhoods had cooler temps which I believe is because most of the sun's rays strike the sides and tops of the buildings, leaving the ground mostly in shade (and so while 5m temps were probably warmer, the 2m temps weren't as warm).

I suspect the cool airport temps is due to all the nearby fields having snowcover until perhaps very recently, meaning it's either going to be very cool due to snow, or slightly cool due to wet ground. There likely isn't any dry ground for quite a distance. Also, there are huge fields there and so the wind is always a fair bit stronger, both at the airport but also in that general area, which on a day like this one seems to have a substantial effect on temps.