I commuted my first winter last year, it doesn't get too bad in Southern NJ, but I still had a few snow storms to ride through. (Yeah Mtn. Bike). The hardest thing for me to deal with was the lack of energy from breathing the extremely cold air. To give you an idea of how cold it was, my water bottle would freeze by the end of the 20 minute ride. Just dress warm and in layers with a nice windproof/waterproof shell.