I'm going to guess that you're a really good shape that a 2 km walk isn't a big deal, but I don't think most Americans can do that.
Shit that's horrifying.
I have health issues and walking 2km a day to try to help fix. So I see 2km a day as basic. 6-10km run a day would be "fit" IMO. things as humans are designed to walk.
Living in suburbia means I have to walk "for the sake of it" although I cam make it useful e.g. get some milk!
As for cold. Anything above minus 5 should be OK just wear stuff like skiiers wear which can be got cheap off brand.