17 degrees when I left the house this morning. I thought it'd be a good day to try my Gerbings battery powered liner vest...turned it off after about 10 minutes because I was too hot. I also started with my snowboarding gloves, but had to trade them for my lighter pair. My ski goggles stayed on though. I also found out that the liner for my motorcycle pants works awesome over tights for my next sub-20 degree commute.