Cover your head.

It was supposed to get cold (below 40 deg. F) last night, so when I headed in to the gym this morning, I expected to be shivering. I had on my shorts and T-shirt, a medium-weight jacket (zipped up), and a knit hat and some gloves. It was just about 40 F, and I was comfortable, even though my legs were exposed. I didn't wear the sweatshirt I brought. I think the difference was covering my head and hands.