I'm interested in purchasing cold weather sleeping bags for my wife and myself. We'll be using them for backcountry snowshoe and cross-country ski camping excursions. What is your advice regarding proper winter bag sizing?
For winter camping, keep this in mind: when you wake up in the morning, everything that was wet at bedtime will be frozen solid when the sun comes up. So, I recommend going with a winter bag that has an extra 8-10 inches of room at the bottom. You'll want to stow water bottles, boot liners, socks, and any other clothing that is damp down there. As for the girth, look for a bag that has a bit of wiggle room for any extra clothes that you might want to wear to bed. If the fit is too tight, you'll be constricted and cold. A key feature in a winter bag is a good draft collar-an insulated tube or yoke around the neck that will prevent cold air from sneaking in and warm air from escaping. Also look for a draft tube that runs the length of the zipper-to keep cold air from sneaking in that way. When I'm winter camping, I always snuggle up with a hot water bottle. It quickly jump starts your internal heater at the end of a frigid day, plus you'll have tepid water to guzzle first thing in the morning.