Daryl should be able to help with this question. He lives darn near the North pole!

As for me, I've shot a lot of muzzle loaders, but when the weather is in the teens down here in Virginia I try to stay by the fire!

For what it's worth, lately I've been lubing my patches using NAPA soluable machine oil and water, about 1:10. Again, I haven't tried this in cold weather.

Good luck!
Curl