As winter weather creeps its way across the country, there’s a good chance you’re packing up your warm-weather gear, which includes any number of summer sleeping bags. But what if you’re planning a backcountry hut trip or a hunting trip with friends this winter? Odds are you’ll still need a sleeping bag to keep you cozy at night, and only the best cold weather sleeping bags will get the job done. The big, lofty bag acts as a warm, dry cocoon so you can get a good night’s sleep whether you’re bundling up at your local campground or backpacking to Everest basecamp. Essentially, a winter sleeping bag is a critical piece of gear.

Cold weather sleeping bags protect you from freezing temperatures and drafty winds. Army Rucksack Bag

Cold weather sleeping bags come in many varieties, from down-filled, which is light and warm, to synthetic, which is bulky but water-resistant. However, the main question to consider is what temperature rating you need. While sleeping bags ship with the brand’s estimated temperature rating, there’s a lot of variability in comfort level. (For example, the Kelty 0-degree bag has a comfort rating of 17 degrees while the Marmot 0-degree bag is comfortable at -3 degrees.)

That’s why many (but not all) bags are externally tested to verify their temperature rating. “EN [or ISO] gives you three standardized ratings based on the actual insulated properties—comfort rating, lower limit and extreme,” explains Porter McMichael, the assistant operations manager and guide at the International Mountain Guides. “If a sleeping bag has been EN tested, you’ll be able to compare a Mountain Hardwear to a Marmot.” Whether or not the bag’s temperature has been verified, we’ve included a comfort rating for each of the options below, which indicates the temperature that the average sleeper could rest comfortably—without shivering—in the prone position in a bag.

Keep in mind that in order to stay safe out there, you’ll need more than just a winter-ready sleeping bag. “A huge part of staying warm at night comes down to your entire sleep system, which includes your sleeping pad and tent, too,” explains McMichael. With all this information in mind, be sure to prepare for your next winter trip with all the essential gear, and read on for the best cold weather sleeping bags so you can sleep outside, even when the mercury falls.

Weight: 3.43 pounds | Insulation: 650-fill down | Comfort rating: -3.2 degrees Fahrenheit

This ultra-lofty cold weather sleeping bag feels like cuddling up in a cloud. Over the years, this bag has become my go-to option for everything from spring mountaineering trips in the North Cascades to early season backpacking in Olympic National Park to winter car camping in the Rockies.

It’s ideal for both backpacking and car camping because it’s spacious and fluffy, but it also packs down for an overnight trip at a moment’s notice. The hood design is roomy and cozy without suffocating your face (like some mummy bags), and the bottom unzips to provide more space for your feet to move around. This bag is also versatile—when the temperatures rise, you can partially unzip both sides to use it like a blanket rather than an enclosed sleeping bag.

Weight: 4.56 pounds | Insulation: 550-fill down | Comfort rating: 17 degrees Fahrenheit

For car campers and occasional backpackers who don’t care about weight, this is a great value sleeping bag for the price. It adopts features found on more expensive bags, like an ISO rating and a well-designed collar to keep out drafts and bitter cold. But what I love most about this bag is the material—it’s softer than any sleeping bag I’ve tried and feels wonderful against your skin when the time comes to cozy up.

While this bag is great for most vehicular adventures, it’s not as good for human-powered travel. Its pack size is large, and it’s at least a pound heavier than comparable models, so I don’t recommend fixing it to your pack unless absolutely necessary.

Weight: 2.56 pounds | Insulation: 800-fill hydrophobic down | Comfort rating: 14 degrees Fahrenheit

Whether you’re backpacking in the rainy Pacific Northwest or ski touring in the Northeast, this cold weather sleeping bag is a great companion for all your adventures. It packs down small enough to fit in any pack and weighs about two-and-a-half pounds. The back of the bag features straps that you can attach to your sleeping pad so it doesn’t shift as you sleep.

It comes as no surprise that Therm-a-Rest uses top notch materials to create this bag. The 100% recycled nylon shell is lightweight yet durable, and the hydrophobic down is suitable for all weather conditions because of it’s moisture-wicking, fast-drying capabilities.

Weight: 2.87 pounds | Insulation: 750-fill UltraDry down | Comfort rating: 15 degrees Fahrenheit

Mummy bags are widely considered a backpacking staple because they feature excellent thermal retention but if you’re a restless sleeper that tosses and turns, you probably understand the drawbacks of a bag that locks you in place. For those in need of a little more room to move in the middle of the night, the Sea to Summit Ascent is the solution. It’s similar enough to a mummy bag such that it will hold in body heat, but it’s also roomy and rectangular enough that you can sleep on your side without worry.

It has other impressive features, too: the zipper system allows you to easily dump unwanted heat if you sleep hot and the hood cinches down to keep heat in if you run cold. For those that wish to stay connected to the real world, an internal stash pocket is big enough for a phone (which is also important in freezing temps!).

Weight: 3.87 pounds | Insulation: 900-fill down | Comfort rating: -25 degrees Fahrenheit

Serious trips to places known for cold weather require a sleeping bag that retains warmth like no other. That’s why McMichael directs clients to the EX Peregrine -25 when they’re looking for the best expedition bag. “Until you know how each company does their warmth ratings, its hard to look at a bag and know exactly how warm it will be,” he says, “but this -25 degree bag is probably similar to other companies’ -40s.”

This sleeping bag has everything you need for an extended backpacking trip or full-on Arctic expedition. It’s wide and spacious in case you need to sleep in insulating layers, like puffy pants and a parka as McMichael does in the coldest climates. It features a draft tube along the zipper to prevent air from leaking in. And the shell is water-resistant to prevent your bag from getting wet as a result of morning condensation.

Weight: 2.56 pounds | Insulation: 850-fill down | Comfort rating: 12 degrees Fahrenheit

It’s almost hard to find a bad review about the Mountain Hardwear Phantom 0; this bag has a cult following for being one of the warmest and lightest bags for its temperature rating. It’s ideal for backpackers, alpine climbers and mountaineers who are focused on weight and warmth. It also comes with its own compression sack so you can get it down to the smallest packed size possible (although we don’t recommend storing it in the compression sack for long periods of time).

The 850-fill down creates a super lofty bag and the water-repellent finish prevents water from beading up on the shell as you sleep. However, the slim mummy shape is incredibly snug and not ideal for those with broad shoulders or wide hips.

Weight: 3.87 pounds | Insulation: 800-fill down | Comfort rating: -29 degrees Fahrenheit

Just to reiterate: a -20 degree bag will be overkill for most casual winter campers. But if you intend to venture into harsh, wet conditions, your sleeping bag choice matters. “When you’re sleeping in temperatures like -20, the inside of your tent will be covered with a thick layer of frost in the morning,” explains McMichael. “and if you’re somewhere like Denali that gets cold at night and warm during the day, then it’ll frost and then melt and your sleeping bag will get very wet even if the air temperature doesn’t approach freezing.” That’s why low-temp bags, like the Nemo Sonic, come with hydrophobic down and a waterproof coating that’s thicker than traditional 0-degree bags.

But the Sonic takes it a step further, too. The toe box is designed to retain warmth and act as a waterproof barrier so you can dry clothing inside your sleeping bag. It also features Thermo Gills that vent heat without risking cold exposure, and a stretchy design allows you to roll onto your side while minimizing the bag’s footprint. If you don’t need the low temperature rating, Nemo also makes this bag in a 0-degree version.

Weight: 5.7 pounds| Insulation: Synthetic | Comfort rating: 13 degrees Fahrenheit

A synthetic sleeping bag is never going to live up to the packability and warmth of a down bag, but synthetics do have their various benefits, one of which includes affordability. And if you don’t need to carry your cold weather sleeping bag on your back, it’s well worth considering the Bozeman bag. This Mountain Hardwear model is bulky and heavy, but for a synthetic bag, it’s incredibly lofty and warm.

It also incorporates a few features that make it stand out among synthetic bags: It has a draft tube along the zipper to keep out wind and a draw cord at the hood to cinch it down when you need to lock in the heat. Also, the fleece-lined stuff sack can double as a pillow if you stuff it with clothing. Ultimately, this isn’t the lightest bag to make the list, but it is a great choice for car camping through winter months.

Weight: 3.7 pounds| Insulation: Down and synthetic | Comfort rating: 17 degrees Fahrenheit

When you don’t want to buy a separate sleeping bag for winter and summer camping, the North Face One Bag does it all. The innovative three-layer system means you can tailor this bag to any season. For freezing temperatures, double up the cozy, 800-fill down mid-layer with the synthetic outer layer, or shed weight when you don’t need the added insulation. For three-season backpacking, simply use the down blanket on its own for 20-degree comfort, and for hot weather, pack the lightweight outer layer that serves as a 40-degree bag.

Because this bag mixes down and synthetic materials, it’s not quite as packable as all-down cold weather sleeping bags. However, at 3.7 pounds, it’s still light enough to take backpacking when you’re not trying to shave weight.

We’ve consulted with experts, scoured reviews and tested products in the field to bring you some of the best cold weather sleeping bags for any adventure. For this roundup, we chatted with Porter McMichael, a mountaineering guide with experience in some of the coldest places in the world: Antarctica, the Himalayas and Alaska. Plus, as a former backpacking guide, I’ve had extensive experience recommending gear, including sleeping bags, for overnight trips in high alpine regions like the North Cascades in Washington that receive feet upon feet of snow each year.

As we considered which sleeping bags to include in this roundup, we compared features side-by-side to determine which bag is appropriate for every possible scenario. We also follow brands to stay up-to-date on new releases and improvements, so you can rest assured these are the best cold weather sleeping bags available right now.

Here are a few key factors to consider when shopping for a cold weather sleeping bag.

For anyone venturing into the backcountry or embarking on a multi-day expedition, a sleeping bag that’s filled with down will offer impressive warmth and a slew of additional features. Down bags are warm and lightweight yet generally more expensive than synthetic alternatives. “I find down to be more comfortable as well—the way it falls and its softness,” says McMichael. “It’s a comfy material.” Down’s major downfall, so to speak, is that it doesn’t stay warm when wet, so it’s important to keep it dry and protected from the elements, especially if you’re using it in the snow.

Synthetic bags, on the other hand, will be much bulkier, especially if they feature low temperature ratings, so they’re not a great choice if you need to carry your gear on your back. With that in mind, consider using a synthetic bag when car camping, or understand that it’s going to take up a lot of space in your pack. Unlike down insulation, synthetic materials retain their warmth even when wet.

A sleeping bag’s temperature rating is an important consideration for cold weather camping. While options abound, we recommend choosing between a 0-degree bag, a -20-degree bag or a -40-degree bag. A 0-degree bag will be a good all-around cold weather option that you can use in the midst of shoulder season. It provides decent warmth in a more packable format. “A 0-degree is a really versatile bag because it will keep you warm pretty much anywhere and won’t be massive, heavy and annoying to carry,” says McMichael.

For extreme environments, you’ll want a -20- or -40-degree bag. “What I tend to see is that most males are fine with a -20 [bag] in the coldest places on earth—Antarctica, Everest, Denali, whereas females tend to sleep colder,” explains McMichael. “This is certainly not always true, but anyone who tends to sleep cold prefers a -40 in those situations.”

“One technology that we see really with only -20 and -40 bags is a waterproof or nearly-waterproof outer shell,” explains McMichael. This shell protects you from the melt-freeze cycle of condensation that builds up in the tent in freezing temps.

The shape of a sleeping bag is also worth considering. Mummy bags, which start wide at the top and taper at the bottom, will provide the most warmth. However, some sleepers find them claustrophobic and uncomfortable, especially if movement is a prerequisite. In that case, a more rectangular sleeping bag like the Sea to Summit Ascent will provide extra room around the hips and legs, but it won’t not retain as much warmth.

Down sleeping bags are best for cold weather because they provide excellent warmth while remaining packable. The alternative to down is synthetic, but McMichael explains that “the warmth-to-weight ratio for synthetic is not very good, and that’s the primary thing you’re after in cold weather bags.”

Semi-rectangular bags and mummy bags will offer the greatest heat retention on cold nights. The form-fitting designs reduce the size of air pockets in the bag which allows your body to heat the surrounding air more efficiently. Many well-fitting bags also feature a cinching hood design that seals in heat, a noteworthy detail that differs from the open, airy design of a warm-weather bag. It’s worth noting that semi-rectangular and mummy bags restrict movement, so don’t pick one up if you’re used to tossing and turning at night or spreading out.

Digital Uniform The lowest temperature sleeping bags available offer protection in -20- and -40-degrees Fahrenheit conditions. McMichael explains that while there is a huge difference between a 0-degree bag and a -20-degree bag, “the difference between -20 and -40 is not big at all. It’s pretty much the same sleeping bag, the -40 degree model is just better suited for colder sleepers.” While you may see some bags marketed as -60-degree bags, like the Feathered Friends Snowy Owl EX, this is uncommon and not externally tested.