31, male, been commuting for just over 2 years.
20 km (12 mile) R/T, 5 days a week.
I ride most of the winter, unless there's deep snow, widespread ice, or extreme cold (which I say is anything less than 0 F). I listen to the traffic report in winter--any time that the number of accidents suggests that drivers are incapable of avoiding each other, I leave the bike in the shed and take the bus.