Nothing new for us Canadians eh?
I have this dress plan when I have to walk in a ways and I know I might sweat. First and most important is wearing a wick away garment against your body. Lots of brands these days (Nike dry fit, body armour etc) then I wear a thick cotton shirt over that. By the time I get to my stand the wick material has pulled all the sweat away and the cotton shirt is wet. This comes off and goes in a platic bag in my pack. I wear just the jacket I'll be hunting in to get in there and bring a warm wool sweater in my pack which goes on in place of the cotton shirt. I might throw another long sleeve warm shirt in there if it's really cold but put it on at the stand. You don't want to be too warm walking in and get all sweaty. That is the killer! I find the prickly wool sweaters I used to hate as a kid to be the best at keeping you warm. The jacket has to be wind restistant as well. Temperature is nothing at all really. It's wind chill that can get ya!
Keeping your feet and head warm is crucial as well. Don't wear so many socks that your boots fit tight. This reduces circulation and makes you feel colder. If the boots rated for the right temperature just wear a comfy sock that wicks as well.