As long as I have a chance to get used to it, I can handle it fairly cold. Even around 0 F recently didn't feel too bad. But when it's both windy and cold, then I give in and put on the long undies (though under ripped jeans) and many layers of tops. My lungs give out first (asthma sucks), but I've been doing ok this winter. I haven't had time to get out and shoot, though - that'll be the real test. Just check the recent temps for southwest Iowa - mostly single digits (except last Saturday - 50s ) and some nasty cold windy stuff coming this Sun - Tues.
Stay warm all you guys who aren't used to cold!