I ride all year round, in all weather excepting thick newfallen snow, but to be honest - if I weren't commuting by bike I'd probably think of a more pleasant, indoor type of exercise on the worst days. Wind I don't mind, cold I don't mind, light rain is fine, heavy rain is bad, rain plus wind is worse, wind and wet falling snow/slush is the worst.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett