Just back from a ND hunt, cold, wet, and windy. I wore two sets of polypro longjohns, loosely belted pants and shirt, an insulated vest, an insulated coverall. Up top a neck gaiter, insulated "radar" hat and/or wool stocking cap, headnet. On my feet, polypro sock liners, medium wool socks, heavy wool socks,and felt-lined pack boots or Bean boots. Two pair of military surplus wool glove liners.
It froze at night and didn't get above 40 during the day, with wind averaging 20-25mph. Even the locals were complaining about the weather. Sweating was not a problem! We ate and ate and ate, and burned it all up in the cold wind.
Saw more big whitetail bucks than I've ever seen anywhere before. Got one picked out for next year...