Warmth is essential to surviving winters. The two major components of warmth are warm houses and clothing. A warm house is any house with an adequate supply of firewood or coal
Clothing is made by a tailor and allows your people to be out in the cold for longer periods of time. Hide coats and wool coats give citizens the same amount of warmth, but warm coats give double that.
Citizens return to their house around 4 times per year without clothes, and fewer times when they are wearing clothes.