There have been lots of folks who have smoked in really frigid weather with no problems. I pulled up this posting using the search feature. Probably the biggest challenge will be getting the smoker up to temp with cold meat. After that it should be smooth sailing/smoking. There are more posts that may instill some confidence/have helpful hints so give it a shot.
http://smokinitforums.com/index.php?topic=4425.msg40580#msg40580