thermal inversions

Any where else, besides the Southern Apps., have to deal with these things? I've replaced all of the half zip Marmots with full zip WM and it's still special trying to plan for night temps. Guess I could move from bivy to tent for better venting but I don't like tents.

It's a relatively common thing up here in the winter time. Not sure it'd make much
difference in the bag I'd be taking though. It means you get ice fog, but at those temps
condensation and wetting out of down due to freezing moisture is enough of a concern
you already have to be darn careful.