I love winter running. I try and only use the treadmill for speed work. The trick is to be prepared. It has taken me a few years to perfect my layering system. Some of the tricks that I have learned is to start with a wool base layer. I also use hand warmers in my gloves and a mask or buff on my face. When I finish I have a thermos of hot tea and a change of cloths and shoes. I have found that these workouts have helped me mentally and physically during racing. So bring on the weather.