I need a pair of shoe covers. What's good for riding down into the teens with MTB shoes?

I've decided to "not" get a pair of Sidi Winter Cycling Boots with a new set of Dura-Ace 7900 Pedals to ride this winter
(along with plans for a new wheelset). Just doesn't make sense to put so much beauty on a bike just to gunk it all up
and subject it to the hazards of cycling in the suburbs & streets of New York City. I'll save the pretty stuff for the Spring.

I'm going to keep my current cheapie Wellgo MG-8 road SPD pedals and use my
Shimano MT-41 MTB Shoes and my Carhartt Wool Work Socks for several reasons.

No need for blingy shoes/pedals in poor weather/conditions.
More stable footing during stops on snow/ice covered roads.
Won't be riding near as much as I usually do,
so performance is secondary to protection from the elements.