Everyone goes on and on about white pants for the winter, but really what I see every year are the white dresses and skirts.
It seems to happen every year sometime after Groundhog Day. The white dresses come out and are re-purposed for cooler weather.
They are layered with tights and boots for places that are still truly cold. And for places like where I live - where it is chilly but you can still get away with bare legs on some days - you simply pair them with some close toed shoes, a long sleeve top and/or a sharp jacket.
Images from Blushing Ambition, Where Did U Get That, Vanessa Jackman and WWD.