I am giving you folks a shot at this one.
It is 20F outside, humidity 61%, the sun is shining on the ISS Mast. I have two anemometers, one is mounted high (I had it up there for about 10 years now , when I could remove the mast and put it up there, now ..not going to happen.) and the second one is down where I can get to it. the Top one is hooked up to the ISS and the bottom one is hooked via the wireless anemometer transmitter. It has been there I'd say maybe 5 years with no problems.
No freezing rain, or precipitation since Thursday.
The bottom one is pointing to the East and the Top to the west and has been that way for about 30 minutes with the cups rotating. The top one is the correct direction, but the bottom seems to have a mind of its own and it does rotate when thwacked with the ice brush thwacker.