I don't ride on the road in sub freezing temps because I am afraid of black ice. I can deal with the cold and have my wardrobe figured out, so if it is really cold, I ride on the trails with the cross bike.

However, if it is less than 20-25F, I ride indoors. Unfortunately, this is most of the winter. . . However, I try to look on the bright side. Indoor training, done right, can be a fantastic way to build fitness for the spring. Riding outdoors this time of year is fun (because riding is always fun), but I can't really get any actual training in. So, now is a building phase, indoors, on the trainer, so that I can peak for early season races that happen just when the snow starts to melt!

. . . . but if we get a rare warm day, you better believe that I'll toss that training plan in the trash, get on my bike, and ride outside - that's what keeps me loving the sport, and feeling like a kid on a bike :-)