If I read this right, the 75 has much wilder swings than the 31. So, with the 75 it could literally display 75F one second then 70 the next? If so, not what I'd want, it took me long enough just to get use to the 31's swings.
No wonder why ASOS's use an averaging algorithm.
That's a little extreme. my biggest 1 min swings are generally 2-3F and usually during the day with a lot of mixing. I decouple easily at night, but occasionally we'll get a puff of wind to mix down some slightly warmer air aloft. That's what those nighttime spikes are.
I am also heavily forested to the west of my property. So there's a bit of a battleground in the early evening between that and the warmer, more mixed air over my field. You can actually feel the temp change on your skin sometimes depending on the direction of the wind. Eventually the field decouples fully and we slip into a more stable, cooler airmas at the surface.
Randy's response is probably somewhat cut back with the filter and the passive shield. I'd be interested to see how his 75 performs in the suped up FARS.
Edit...just wanted to add that I don't think most of you would see the swings on your 75s that I see. From what I've seen of the siting around all of your stations (Valentine/Tucson/Victoria), your geography is fairly consistent for many square miles around you. My clearing surrounded by tall pine forest acts like a seabreeze when the wind and mixing aren't strong enough. I'm on the north side of a hill too, so we struggle to lose surface moisture so the evapotranspiration keeps the dewpoints a little higher and the temp a bit lower (again, when mixing is weak). My dewpoints tend to fall more in line with ASOS during the cold season.
