Originally Posted by
JohnDThompson
I use fleece-lined bike shoes when the temperature drops below about 50°F. When it gets below freezing I add neoprene shoe covers and sometimes catalytic toe warmers.

I'm impressed that this gets you through a WI winter. Personally when it gets cold, I ride an old mtb with platform pedals so I can use my winter boots. I haven't figured out how to make them SPD compatible,