Bike shorts, mid weight Patagucci capilene longjohns, REI windfront tights. Good to below zero F. (-18 C or so) Throw a pair of fleece pants on top of those and you're good down to -20F (-29C) I don't ride if it's more n' -20F. So call me a wuss. Too many bad things can happen really quickly at that temp.

Adventure is just poor planning- Inuit saying.