I have been hitting tennis at night around 8 pm or even later and it is cold here where i live, but after the first 30 mins hitting to warm up my body is kinda adjusting to it and it doesnt feel that cold at all (i played the night before and temperature was 28 F of course without wind). My point is as long as its not windy, outdoor tennis is still possible even at 30ish Farenheit temperature. I breathe out smog also and its fun to get a match on. Whats your extreme playing condition so far? I wouldnt call mine extreme yet.