I just wear tights and change when I get to where I'm going, but my dad has these: swrve ? Winter Softshell Trousers

They're pricy, but my dad is a frugal man and still thinks they're worth it. He wears them from about -10º to 40º F. I think he also has a pair of the mid-weight trousers for spring and fall. He wears them pretty much the entire week and doesn't have to worry about them starting to smell.