I have flown in -25C/-13F once and only once. The receiver battery only lasted for one flight, and that was more than my fingers were comfortable with, even with gloves. Last winter it stayed below -30C/-22F for several weeks, so I took a break from flying -40C/-40F is the coldest temp I have seen here. Between 15C/59F and 20C/68F is perfect IMO. No need for a jacket, and not too hot. Anything hotter than 25C/77F is uncomfortable to me. And some of you guys are flying in 100+ F. That is impressive! Maybe I should go to Australia next winter and see if I can learn how to survive in hot weather. I'm just not built for anything more than 25C...