Warning: the guy at the Reno REI talked me into a 20 degree bag for a 35 degree trip, and I froze
He said the rating was "comfort" not "survival" so I'd be fine in just a base layer, and I shivered till 4am at Tahoe. What temp bag do you all actually trust on a cold night?
Ugh been there! I did a trip near Truckee in a 20 degree bag when it hit like 30 and I was miserable too. Now I always bring a bag rated about 20 degrees lower than the coldest temp I expect and add a liner, that combo kept me toasty down to the high 20s no problem. The rating on the tag is pretty much a joke unless you're wearing a full puffy inside it.