Geno,
I shot this warrior in the last minutes before closing on your birthday 12/31/09 and recovered him News Years morning at sunrise, -15 degrees.
I only hunt the hours that I feel that I am going to see deer, namely the last 2 hours of the day. I know where they are going to appear and plan for that ambush.
I can do anything for two hours and seldom get cold, no matter how cold it is. De-scent prior to the hunt in a nice HOT shower, dry yourself thoroughly but keep your core hot.
***Trick - I throw my merino underwear in dryer to warm-up, plus hat, socks and whatever else. Do NOT overdress. Loftiness is important; your body has to breath and ventilate. I wear XXL, leather, fleece lined, Chopper mittens and shoot bare handed and bare-fingered.
I DO NOT wear a face mask, if you want to miss a deer bowhunting...wear a face mask IMO. Unless you practice with one on all the time, it is the worst thing you can do for your anchor. Don't bother going out if you are not going to sit on something soft and warm, i.e. foam seat cushion, two of them preferably.
I LOVE late season bowhunting, it is my preference! Overcoming the elements is half the fun. Harvesting an animal is bonus but when you do it, it seems even more special.
Kris