I've only used the stock cantilever breaks on my 12 year old MTB and I've never had problems due to cold and I've ridden in temps well below 0 F.

Along with colder weather, road conditions usually aren't that great this time of year so I don't expect instant stops, - my wheels would just lock up.

Is this a road bike and did the release accidentally get flipped? It sounds like that's what you're describing. Maybe something happened to the brakes and the cold is just a coincidence.