At least it seems to me it is. The trend / tendency / craze / obsession / delusion that I thought was just confined to hipster high school students. It's now moved on to older folks as well.
No, it's not Justin Bieber, Taylor Swift, or the latest smart phone app. It's the notion that no matter what the temperature outside, they MUST WEAR SHORTS!!
I don't know if it came from marketing, or is a derivative of the "coats aren't cool" concept, but I've observed for months now that more and more people, at least in my area in Western Maryland, appear on the streets in shorts during the cold weather. Most of them are guys. (I suppose I wouldn't complain nearly as much if it were mostly girls).
I've come to the conclusion that the threshold is about 40° F. Any time the outside temp goes to or above that level, the uncovered knees appear. The strangest ones to me are those that come out in a full winter coat, hat, and maybe gloves, but still sporting the jogging shorts. But the majority are dudes with hoodies or warmup jackets and athletic shorts, low socks and sneakers running around in the dead of winter. Now, I give a pass to the guys just coming off the basketball court in the local gym, but you can usually tell if that's the case.
My theory is that they're either just running a higher metabolism, or hopped up on energy drinks or coffee, or they have some new ailment that makes their knees 20° warmer than the rest of their bodies.
I was trying to think of what to call it. Steamy knees? Swelter shins? Parched Pants? Tropical Trousers? Baking Britches? I could go on...