I don't know what it is but as the cold weather has swept into the northeast (and it hasn't even been THAT cold) I'm really feeling it. I can't ever recall feeling so uncomfortable in temperatures in the low 30's. As recently as last year I was finding 32 degrees to be my favorite bike commute temperature. Mostly it's my hands. Usually they don't hurt until it's down in the teens. This year they hurt at about freezing.
This cold intolerance has put me off cycling in the late fall. I was on track to be easily over 3000 miles this year. Now I'm going to have to scrape together 57 more miles in December to make that!