Snowy roads will force me to find another way to commute to work, but the cold usually doesn't stop me. It rarely gets colder than -30C here in Calgary, and that's my rough limit. Anything colder than that, and I find I have to bundle up in too many layers to enjoy the ride. There is definitely an art to finding the right clothing to enjoy being outside in the cold, so it may be that I just don't have that experience yet on those really cold days.