Lots of people have trained in the cold for a very long time. Clothes and warmup are a very effective solution to this problem. Heat is much less fun, because you can't take off enough clothes to make a 107-degree weight room comfortable. The heat is friendlier to joints, connective tissue, and muscle bellies, while the cold is friendlier to sweat glands and my general demeanor. Given the choice, I suppose I'd rather not get hurt as easily, so I'd take the heat, as much as I hate it.