Cold weather. Fighting through the cold to get to being warm is so much more tolerable than fighting through the heat to get to being cool. And yeah, a lot more feasible in most situations to bundle up than to remove layers. Of course, I live in a desert so I savor the 30-90 days of tolerable weather before dealing with the Long Summer again. The heat is like stepping into a convection oven sometimes. The wind just feels like a heater blowing in your face. Staying cool is expensive to do well with an A/C, and evaporative cooling doesnt always work well. Meanwhile, blankets are cheap.