Greetings from Minnesota! I've been reading here a while, and this is my first active post. Winter clothes is something we know about here
Layers are the key, as mentioned. There are natural options that work as well as or better than modern synthetics. First, silk as a base layer next to the skin. Second, one or two wool layers as insulation. Last, a windproof outer shell, like a cotton anorak. This is geared towards really cold weather - a plain cotton outer layer will not work as well if it is warmer (wetter). Waxed cotton/canvas is really great stuff, but it can get stiff when it gets cold. Once you are at -10 F or colder, there really isn't too much danger of wet feet or wet precipitation unless you are in town where the streets are salted. Well, maybe if you are ice fishing and you get lake water up through the hole.
If you want to get away from production fabric, the real choice to me is fur. Caribou, bear, bison, sheep - it doesn't really matter, though some are better than others. No spinning yarn, no weaving, no raveling. Tan it and make it into outerwear. You don't even need to be a hunter if you don't mind getting into roadkill and the local wildlife dept approves. Traditional sinew is easy to work with and actually quite simple to produce. Best stuff comes from backstraps and legs of large animals, like deer/elk/cattle. The Traditional Boyer's Bible book set has multiple sections on obtaining and using sinew. There are other resources online as well. Google will help.
I find that water is the hardest thing to manage with natural fabrics. Cold is fairly easy. Traditional mukluks keep your feet toasty, but they are made for dry snow, not slopping around in slush. Once you are in the warmer portion of winter, you will likely want your outer shell to be waxed canvas rather than the plain tight weave canvas.
You can get pretty much all the natural fabric cold weather gear you need from these guys, as long as your pockets are deep. I bet it will last you the rest of your life, though...
http://empirecanvasworks.com/
Another place that has canvas anoraks:
https://www.duluthpack.com/apparel/men/mens-jackets/canvas-anorak.html
I'm not affiliated with either of these, but I do believe in their products, especially Empire Canvas.
