secret is layers. Dosn't matter how stupid you look as long as you are warm when you ride and you have some protection. Wear your summer coat with another over the top............
Another trick from riding in severe cold was to put a garbage bag over my sweater and under my jacket. Acts as a wind resister and help insulate you.Y ou will sweat some but if you are in severe cold and running hard like on a freeway you will stay warm.
Years ago I wore belstaffs and rubber boots and bread bags over my gloves to keep them dry. Wet leather is gonna be cold leather real quick and you'll freeze.
Everyone made fun of me, but after 300 miles in the rain, I was the only one warm and dry. Screw them.