Our smoke yesterday started @ 20*F. The only problem was it took a bit longer to get the cooker up to smoking temperature. We had a first--the doors on either end hung and wouldn't close well until the vessel's temp evened out. They were cut with a plasma torch and have really tight tolerances. The doors expanded before the ends of the tank did.
Once uniform temperature was reached, it was all good. The doors didn't hang any. Initially, it took more wood. Once we were at cooking temps, wood consumption seemed pretty normal. The high for the day was around 32*F.