Several of our tents are rated for very cold camping, but how to stay warm camping in a tent can still take preparation. You want insulation that will trap as much air as possible in the tent. You can use insulation on the outside or inside of the tent. Foam is great for insulating the floor (remember to go a little ways up the walls as well). And finally, insulate yourself! Get a cold-weather sleeping bag, pack a super-warm fleece, and don't sleep on a raised camp bed.