I am a wimp and won't even consider commuting (and then only about once a week) unless my morning start temps are 40 or above (and not too windy). But my DH has decided to go for the "perfect commute year" and so far is doing it. He has all kinds of wool sweaters, and gloves but rides in mountain bike shorts w/o any other leg coverings. No snow, but Tucson got hit with record-breaking cold temps this week (In the teens plus wind chill on Thurs and Friday). He was determined to ride. It was like pulling teeth to get him to wear sweat pants over his shorts on Weds at 30 degrees, and one more extra layer for the real cold on Thurs and Friday... He said he wasn't cold. (But I don't know if he would admit it if he was...