It’s one thing to be cold at some point while skiing, snowshoeing or hiking in the winter, but for most people the thought of sleeping in a tent in winter (or any temperature below freezing for that matter) is a deal breaker. While I may be a bit biased on all things cold, ice and snow, I do feel that there are a few basic steps you can take to ensure every night in the tent is a warm one—no matter how low the mercury drops.
1. Stay Dry – Your clothes or sleeping bag … they both work best when your body can keep a warm layer of air close by. Add in sweat, wet socks, or a damp shirt and that warm layer of air is replaced by heat-sucking water. Do yourself a huge favor by starting out your night in completely dry clothes (and sleeping bag).
2. Use Your Sleeping Bag Properly – staying warm means not letting valuable heat from inside the bag escape. Sleeping bags are designed to be zipped and cinched. Make sure the draft tube is aligned properly along the zipper. Also make sure the actual zipper is all the way closed. For extremely cold nights, cinch the hood and draft collar into a small opening around your mouth and nose.
3. Wear More – I’ve never really subscribed to the theory that you should sleep in as little clothes as possible while inside a sleeping bag. It is true that if you wear too much you will overheat and sweat which goes directly against tip number one. Regardless, if you find yourself getting chilled, add another layer. Also, I’m a huge fan of wearing a balaclava and / or hat.
4. Insulate from the Ground – I should actually put this at the top of the list because it is so very important. You end up losing way more heat through conduction (direct contact with the cold ground) than convection (air). Therefore, it is important to have a good sleeping pad. In very cold weather (below zero) I will even use two pads—a RidgeRest SOLite on the bottom and a NeoAir XTherm Max on top. Also remember to re-inflate your inflatable Therm-a-Rest mattress early in the evening as air that was initially blown into it will cool, shrinking the volume of air inside the mattress.
5. Add a Blanket! - This fall I was climbing in Nepal—we didn’t want to bring two sleeping bags—a warmer weather bag for trekking in and a second extreme cold weather bag for above 14,000 feet. Therefore, we opted for a simple solution, we used the Altair down bag for most of the expedition, but added a Regulus Blanket as an additional layer when it got cold.
6. Eat – On the trail food is fuel. It helps keep you going and it helps keep you warm. I usually keep an energy chew/bar close when I’m sleeping. A few bites midway through the night is like putting another log on the fire.
7. Go to the Bathroom – In cold weather most people are reluctant to get out of their warm sleeping bags to go to the bathroom; however, it’s important to heed nature’s call because having extra “fluids” in your body is actually wasting energy that could be used to keep you warm.
Bonus Tip: For longer adventures and consistent below zero weather, try using a vapor barrier liner as it traps in heat but more importantly prevents moisture from getting into your sleeping bag.