There are many backpacking or camping items that you can get away carrying in either summer or winter conditions, but a sleeping bag isn't one of them. You can always add warmth to a summer sleeping bag by using a liner, but this is almost never the most efficient way to go about it. Better to have one summer sleeping bag, and one winter, or 4 season sleeping bag, that you can use when the temperature dips down low. Winter sleeping bags do tend to cost a bit more, and it can seem like a bit of a hassle to have two sleeping bags, but if you want to save on weight, it's a requirement.
4 Season Sleeping BagFeatures to look for when you are reviewing 4 season sleeping bags.
- Down - 4 season sleeping bags can get heavy, which is exactly why you want to get a down sleeping bag, as opposed to a synthetic sleeping bag. The one drawback of using a down sleeping bag as a winter sleeping bag is that down does not handle being wet nearly as well as synthetic insulation. So you have to be sure to keep your bag dry, but as long as you do that you are fine.
- Extras - A 4 season sleeping bag should absolutely have things like a hood, which comes standard on most sleeping bags anyway, and something else you may want to look in to is a draft collar, which sits around the neck and is meant to keep warm air down around your body. It might also be a good idea to get a sleeping bag with a face area that can be tightened down, so that you get a good seal around your face.
Best 4 Season Sleeping BagsA few of the best 4 season sleeping bags on the market, based on the above criteria.
- Marmot Plasma +15 Sleeping Bag - First up, a 4 season sleeping bag for those who are lucky enough to live in a place with relatively mild winters. This sleeping bag is only rated down to 15 degrees, which isn't extremely cold. What this does mean, however, is that it would also be well suited to colder summers, making it potentially useful year round. Beyond that it uses 900+ fill down, which is the high quality stuff, and uses a draft collar and drawcord hood to further insulate you from the cold. It weighs 1.87 pounds, or 850 grams, and won the 2011 Backpacker Magazine Editor's Choice award.
- Western Mountaineering Antelope Gore WS Sleeping Bag - Another very good four season sleeping bag, this one good down to 5 degrees. This bag uses 850+ fill down, which is very good quality, and actually has a Gore Windstopper outer, so if you think there's a chance you might get a little wet, that will help protect the down from moisture, and wind chill too. It also has a draft collar, and weighs 2.8 pounds, or 1.27 kilograms.
- Mont Bell U.L. Super Spiral Down EXP - For those that plan to venture out in to the real cold, there is the EXP from Mont Bell, which is good down to a very impressive -20 degrees. This sleeping bag pulls out all the stops to keep you warm, including a draft collar, a drawcord hood and Mont Bell's unique construction technique, where the sleeping bag is cut at a 45 degree angle, so that it coils around you. It weighs 3.43 pounds, or 1.55 kilograms, which is a lot, but you have to remember that it's also good down to -20.