DU-ers in places that are extremely cold (20 or below), have your brakes checked
if you have an "older" car (e.g., 200,000 miles and above)
Not only for the obvious reasons (pads, shoes, fluid, rust from the salt on the roads, etc.) but for this reason: There's a rubber gasket-like device (the diaphragm) that hardens with use. When the temperature drops, it affects the braking system. In my case, the brake pedal won't go down like it's frozen or glued and consequently you will find yourself moving steadily toward, say, an intersection with no means of stopping or slowing down. Not a good feeling.
As the car warmed up, the pedal could be depressed and the brakes functioning.
But my point is unless the temperature is low and it's happened before, you won't know you have this condition.
Don't wait to find out like me (no problems, no accident) and have your mechanic take a look for you and fix it if there's a problem.
I don't want to be a Cassandra (Greek mythological woman who was cursed with correctly predicting the future but nobody would believe her). You'll have potentially other issues driving in extreme cold, ice, and snow. Remove one more thing to worry about.
My mechanic just told me to always warm up your engines like 5 minutes on really cold mornings/days/nights because if you don't you can't crack and damage stuff like the diaphragms.
Best to you all,
No_h