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8 Best Winter Sleeping Bags for Backpacking & Mountaineering In 2023
Winter can be the best season to climb some peaks, and it’s certainly the best time to head into the mountains if your goal is to ski great powder. But multi-day backcountry trips in the winter can go from fun to miserable quickly if you don’t have the right sleeping bag for the job.
Sleeping bags for winter backpacking and climbing need to be insulated enough to keep you warm through even the most frigid alpine nights. In this guide, I’ll review 8 of the best sleeping bags for winter camping.
My Review Process
One of the nice things about the Pacific Northwest is that it rarely drops below 0°F in the mountains, even in the depth of winter. However, that also makes it more tempting to get out climbing in the winter—so I’ve spent a number of nights out in the cold.
What I’ve learned is that there’s a lot more to choosing the best winter sleeping bag than just temperature rating. Weight, compressibility, and water resistance are also critically important.
In addition, choosing the right sleeping bag requires thinking about your entire sleeping system, including your down jacket, sleeping bag liner, and sleeping pad. There’s no single best sleeping bag for every cold night out, so my goal is to help you choose the bag that’s best for your adventures and your sleep system.
RAB Neutrino Pro 900
All-around Best Winter Sleeping Bag
Great value for 900-fill down
Excellent warmth-to-weight ratio
Internal pocket
Hydrophobic treatment
Rated to -4°F
Hood doesn’t cinch all the way down
The RAB Neutrino Pro is my top pick for any camping trips where sub-zero temperatures aren’t expected. The 900-fill goose down offers an exceptional warmth-to-weight ratio for a winter sleeping bag. At 2.85 lbs, the Neutrino Pro falls squarely in the middle of the pack for weight, but it feels a lot warmer than competing bags.
While hardly cheap, the Neutrino Pro is also significantly less pricey than similar bags. I wish the adjustable hood closure cinched down a little tighter, but it’s tight enough to make sure no heat is escaping around your head.
The internal pocket is a nice touch for storing your headlamp and camera batteries overnight and the snag-free zipper is easy to manage. It also comes with a storage sack. Overall, this is an excellent winter sleeping bag.
RAB Neutrino Pro 900
Feathered Friends Snowbunting EX 0
Runner-up
900-fill down
Pertex outer fabric
Packs down small
Handmade
Lightweight winter bag
Not very roomy
Feathered Friends makes some of the best down gear of any manufacturer, so it’s hard to go wrong with any sleeping bag from this company. The Snowbunting is one of my favorite 0-degree bags and it only falls behind RAB’s Neutrino Pro because of its less affordable price.
The Snowbunting is warm and light, and it features an extra layer of weatherproof fabric that performs surprisingly well against melting snow. It also packs down small with a compression sack, although that’s partially at the cost of less space to move around when the bag is unpacked.
Feathered Friends is a small company and they make all of their bags by hand, so be sure to order this bag a few weeks before you need it.
Feathered Friends Snowbunting EX 0
Mountain Hardwear Bishop Pass 0
Best Budget Winter Sleeping Bag
Budget-friendly warmth
Not much heavier than more expensive bags
Hydrophobic coating
Gore-Tex version available
Narrow profile with little room to move
Mountain Hardwear set out to prove that you don’t have to spend $500 or more to stay warm when camping on snow. The Bishop Pass 0 bag cuts costs by using 650-fill down, but it doesn’t cut insulation. The trade-off is that it weighs in at 3.1 lbs, but that’s not really much heavier than the lightest bags on this list in the big scheme of things.
This bag is best suited for back sleepers and those who don’t toss much at night. Part of how Mountain Hardwear kept the bag’s weight down is by giving it a very narrow taper, so there isn’t much room to move around inside. A glow-in-the-dark zipper pull and oversized draft tube round out the bag.
Mountain Hardwear Bishop Pass 0
NEMO Sonic 0
Best for Comfort
Baffles for horizontal stretch
Available in 0°F or -20°F versions
Great hood coverage
Water resistant coating
Not as warm as similar bags
NEMO has introduced a few unique design aspects to the company’s line of sleeping bags, including the Sonic 0. It offers a stretchy footbox, extra room around the hips, and—most important—vertical baffles running the length of the chest. These baffles allow the bag to stretch horizontally, so stomach sleepers like me can kick a knee out while sleeping. You can also sit cross-legged in the bag before bed.
The downside to the Sonic’s extra space is that it doesn’t feel as warm as bags with the same amount of 800-fill down. NEMO makes a -20°F of the Sonic that can solve this problem, but of course it’s a bit heavier and a bit more expensive. I’d recommend pairing the Sonic 0 with a sleeping bag liner to get the best of comfort and warmth.
NEMO Sonic 0
Mountain Hardwear Phantom 0
Best for Ski Mountaineering
Packs down very small
Excellent heat retention
Best in class warmth-to-weight ratio
Moderate price
Not much room to toss and turn
The Mountain Hardwear Phantom 0 is another top 0°F-rated bag. It’s incredibly warm and surprisingly lightweight for how much loft it offers. Baffles around the head and neck also do a great job of trapping in heat. Another benefit is that it packs down smaller than almost any other bag on this list.
The Phantom 0 isn’t roomy, so those who toss and turn overnight might not love this bag. But if you can live with that, it’s perhaps the best option for fast and light missions—and moving fast matters when there isn’t much daylight.
Mountain Hardwear Phantom 0
Marmot Col -20
Best for Winter Expeditions
Extremely warm
Outstanding loft
Weatherproof shell
Plenty of room inside
Very expensive
Heavy and bulky
If you’re planning winter camping expeditions to Alaska or the Himalayas—or if you don’t let extreme cold change your plans in the Lower 48—then you’ll need an expedition-style sleeping bag like the Marmot Col.
The Col is made with an astounding 44 oz of 800-fill down (most bags on this list have around 25 oz of fill). It also features a weatherproof shell that’s more robust than the hydrophobic coatings applied to most winter bags.
This sleeping bag is very expensive and quite heavy, but you simply won’t find anything better for tackling the coldest temperatures. If you’re spending a week or more in the backcountry in the dead of winter, this is the sleeping bag I’d pick.
Marmot Col -20
Feathered Friends Spoonbill UL 2
Best Double Sleeping Bag
Weighs the same as a one-person bag
Each person gets their own hood
Pertex breathable material
Less expensive than two sleeping bags
Loses a lot of warmth with just one person inside
The Spoonbill UL 2 is one of the only double sleeping bags that’s rated for sub-freezing temperatures. Which is surprising, since sharing your body heat with a partner is one of the best ways to get extra warmth when nighttime temperatures plummet.
What’s really neat about this bag is that it weighs about as much as all the other sleeping bags on this list. But since it fits two people, you’re cutting the weight you and a partner have to carry in half.
Each person gets their own zipper and hood, and the bag features the same Pertex shell as the Feathered Friends Snowbunting. It’s a terrific option if you climb with the same partner repeatedly and don’t mind getting close.
Feathered Friends Spoonbill UL 2
Therm-a-Rest Vesper 20
Best Quilt for Winter Camping
Very lightweight and packable
Relatively affordable
Sleeping pad pocket
Snap closure system to hold in heat
Not as warm as a mummy bag
To be honest, I’d recommend against bringing a quilt-style sleeping bag on winter camping trips. While I love quilts for how comfortable they are, they’ll never hold in as much heat as a mummy-style sleeping bag since they don’t have a full-length zipper or draft tube.
If you’re determined to take a quilt, check out the Therm-a-Rest Vesper 20. It’s one of the warmer quilt bags available and is incredibly packable thanks to its 900-fill down. Additional features include a snap closure along the side and a pocket for your sleeping pad, which helps ensure you don’t end up on the ground at night.
Therm-a-Rest Vesper 20
Best Sleeping Bag Brands
Sleeping bags might seem simple—after all, they’re basically cylinders of down—but there’s a lot of craft that goes into designing top-of-the-line bags. As a result, the world of high-performance sleeping bags is dominated by just a handful of companies even though dozens of different companies make down jackets.
Feathered Friends has a reputation for making some of the best down sleeping bags in the US. Mountain Hardwear isn’t far behind, and offers some value bags for more cost-conscious adventurers. Companies like NEMO, RAB, and Western Mountaineering have all demonstrated that they can make really impressive sleeping bags, too.
How to Choose a Sleeping Bag for Winter Camping
Choosing the best winter sleeping bag is about more than just temperature rating. Here’s what I look at when evaluating bags.
Temperature Rating
The temperature rating that manufacturers give their bags is a good place to start comparing sleeping bags, but don’t take these ratings as indisputable truth. Not all 0°F bags are equally warm.
I’ll get into that more in a moment, but as a rule of thumb, the ideal winter sleeping bag is rated to 0°F—or colder if you’re a cold sleeper. 20°F bags can work in the winter in mild climates like the Pacific Northwest if you’re a warm sleeper, but you may still want to add a sleeping bag liner.
Warmth-to-weight Ratio
The difference between sleeping bags with the same warmth rating lies in the material they’re filled with. When comparing down bags, a higher fill rating means you’re getting down with better insulating properties. As a result, manufacturers can use less down and save weight.
This is why 900-fill down sleeping bags tend to be lighter weight than 800-fill sleeping bags with the same temperature rating. Of course, higher-fill down is also more expensive. So there’s a trade-off to be made between warmth, weight, and cost. Any 0°F sleeping bag that weighs under 3 lbs is doing a decent job of balancing these factors, in my opinion.
Note that none of the bags I reviewed use synthetic insulation. Synthetic insulation simply can’t match the warmth ratio of down, so synthetic sleeping bags end up weighing 5 lbs or more to reach a 0°F limit rating.
Waterproofing
You usually don’t have to worry too much about wet weather in winter. The air is dry, and precipitation is more likely to fall as snow than rain in cold conditions.
However, it’s still important to have a water-resistant coating or waterproof shell around your sleeping bag in snowy conditions. Any snow that gets on your bag will melt from body heat, and down loses its insulating properties once it gets wet. It’s also really difficult to dry down out once it gets wet.
Hood Design
A well-fitting hood is especially important for winter camping because you can have a surprising amount of body heat loss through your head. The best hoods are oversized to completely cover your head and give you room to move around. They also have draft collars and cinch down so that just a portion of your face is exposed to the cold air.
Comfort
If you’re the type of person who never moves while you sleep, almost any mummy sleeping bag will be comfortable for you. But if you’re a stomach or side sleeper, mummy bags can be a lot more challenging.
Roomier bags can feel more comfortable to sleep in, but they also add bulk and leave more air spaces where cold spots can form. In general, go for the tightest sleeping bag that you’ll be able to get comfortable enough to fall asleep in.
Summary
I think the RAB Neutrino Pro 900 represents the best balance of warmth, weight, packability, and cost for winter backpacking and mountaineering. If you’re willing to spend a little more money, the Feathered Friends Snowbunting offers an even greater warmth-to-weight ratio. For winter climbers on a budget, the Mountain Hardwear Bishop Pass 0 is surprisingly inexpensive and doesn’t sacrifice much in terms of warmth.
Common questions
I live in Bellingham, Washington, at the base of the wild North Cascades. Over the last ten years, I've explored much of the region's steep terrain and endless layers of ridges and peaks, both on foot and on skis, often linking far-flung ridges together to push deeper into the range.
*The information on this site is based on research and first-hand experience but should not be treated as medical advice. Before beginning any new activity, we recommend consulting with a physician, nutritionist or other relevant professional healthcare provider.