I'm in Wisconsin and our winters are pretty similar to yours.

Ditch anything cotton and you won't need as many layers. Cotton holds moisture, even if you don't work up a sweat, and moisture is your number one enemy to staying warm while hunting.

Wash your clothes with scent-killer detergent as needed (not after every hunt). Use synthetics (think Under Armour Cold Gear, fleece long underwear) and natural non-cottons (wool, down). Layer clothes--but be sure that they're not tight. Fewer layers is better than tight layers--my hunting jacket and pants are huge to allow layers underneath (2XL). And arrive to your stand slightly chilled and then bundle up to avoid locking sweat into your outfit.

Unfortunately, this meaning buying some hunting clothes--ditch the jeans, sweat pants, cotton underwear, and cotton undershirts.

Also, don't buy cheapo hunting clothes that don't breath. You want some sort of waterproof BREATHABLE outer jacket and pants. I once layered up with long underwear and fleece pants (4 layers?) and had a camo waterproof pant on last. It was cheap and didn't breathe. I ended up with all the moisture from my body wicking outward to the camo pants and then freezing there. I had a layer of sweat-snow just inside my pants because of my low quality camo pants!

Last year's gun opening was cold (below freezing) and I sat on stand from before sunrise to after sunset without leaving once. Getting the right gear and using it right makes a world of difference.