In Alaska if you didn't fly if it was chilly I bet you wouldn't get to fly very much. Farther south if it's too cold you can just wait a few weeks and it will probably warm up at least temporarily. After a certain point it just isn't any fun to stand still outside in the cold. (The same goes for heat too - if it's 100 degrees and humid wait for next weekend!)

I would like to hear your cold weather flying tips though.