How cold can I go? Depends on how cold it can get, I guess. I've been riding an hour to work in 20-22 F for a couple of weeks now. I've got the clothes figured out, but as someone said, the ice on the inside of the face shield is a pain. I need to find a way to stop that.
I also need to find some studded tires, because we generally get a little snow around here in the winter.
Heck, if I didn't ride below 45 F, I'd have 9 miles on my bike this summer instead of 9000.