I'm with Leesa.
Go to a discount sportswear store and buy ski pants or bib-fronts.
Get last year's styles or unwanted colors, cheaper.
They will be windbreakers and keep you dry in the snow, too.
Also silk long johns (LL Bean & others) and thermal long johns, too.
Ski-boot socks are a blend of fine wool that are tall and keep you warm in winter boots.
Fur lined (faux fur or sheepswool) boots and booties and slippers are good too.
Just depends on where you are, as to how cold.
I'm familiar with MO weather. My wife was born & raised in Sedalia.
My mother in law lives in Columbia MO.
It gets pretty cold there too.