I can ride sometimes during the winter - live in Flagstaff. Some winters we can ride all winter long - and can go down to the desert country on weekends to ride too.
However riding after work just doesn't get it. It is cold and dark. So, most of the time, I do other things during the week. I spin at home. I spin usually at least twice at the gym (we have a really great guy who does spin classes for cyclists so it is a class using chris carmichael techniques of training). I do some weights, yoga, etc. If we get good snow, we cross country ski and do hikes/snow shoeing. Winter time is a good time to mix it up. It keeps you from getting burned out on biking anyway.