I have a rule about biking in the cold, which I like to phrase as "never go out wearing all of your gear". That's maybe a little confusing: what I really mean is "always bring spare gear with you". This morning's 15 degrees was cold enough for the neoprene face mask, and any colder and I'd want the glove-liners in my pocket in addition to the winter gloves I had on my hands. I have a spare pair of socks here at work with me in case it gets really bad. At some point I should look into neoprene overshoes that work with street shoes as the winter bike does not have clipless pedals (and now that there is salt on the ground, the summer bike won't come out again until after the second good rain in spring).