Summer vs Winter Temps

So, I've been wondering: why in the winter does 50 degrees feel warm and we're outside in shorts basking in the pale sun, while the same temperature in the summer is frigid and requires a coat?

This has been a topic of much discussion in the Phouka household this week. We open the house up at night to take advantage of the lovely Colorado summer weather, and the temperature in the house in the morning has been dipping into mid-50s territory. It's perfect sleeping weather, and if we are conscientious about shutting the windows in the morning, the house stays cool enough that the air conditioning doesn't really come on until early evening, even on the 90-degree days. That sun blasting into the house from the west tends to heat things up a bit, but otherwise, it's pretty comfortable. The temp outside was 85, and even at 4pm it was still only 68 in the house.

Anyway, it's pretty dang chilly in the house in the morning, and even cooler downstairs. The Adorable Husband has been exercising in the basement each morning, and enjoying the cool mornings. I had to laugh at him -- if the house was the same temperature in January, say, he'd be bitching to high heaven that the house was like an icebox and refusing to get out of bed in the morning! (Well, me, too, but I tend to like it cooler than he does in general).

But now? When the days are climbing to 90 degrees? It's "refreshing" and perfectly ok that the house is at 56 in the morning while he runs around in pajama bottoms and no slippers.

Well, why does this happen? Obviously, it has to do with perception of "hot" and "cold" compared to the normal environment (I found an interesting explanation here in Hot and Cold Questions), but my body temperature is the same. Do I just get used to it being warmer, so my body thinks that 75 degrees is the "right" temperature instead of 35 degrees? So at some point in the spring and fall my body temperature sensors readjust? What triggers it? Average outdoor temperature? Longer daylight hours? Humidity?

It's all a sensory illusion, of course. 55 degrees is 55 degrees, but the relative difference in what we see as "normal" temperature accounts for the difference. I'd be curious, though, to find out the specific trigger points for when we think 55 is hot vs when we think 55 is cold.