I set a new personal record today: Lowest temperature for a tube change: 20 F. It was on a stretch of road with only private residences, so I couldn't go inside anywhere; I just found a cleared driveway to set up in. (We got about an inch of snow last night.) Fortunately I was dressed well enough so that the only annoyance was that I had to keep taking breaks to warm my hands up, after needing them bare to work. When I got to work, my hands and feet were both slightly uncomfortable, due to being out longer than usual, but nothing dangerous. Delayed me about 25 minutes, including the 3 minutes spent conversing with the nice older gentleman who came out of the house to make sure I was okay, just as I got the wheel back on.