7 Best Cold Weather Sleeping Bags for SUB-ZERO Survival [2018 Update]

Mother Nature doesn’t mess around. If you’ll be camping in bone-chilling conditions, you need to see our list of the best cold weather sleeping bags.

Did you know that it takes just over 10 minutes for a person to get frostbite in 0°F temperatures with only a mild wind?

Now imagine 8 hours of unrelenting cold overnight.

Your sleep system is your last line of defense against injury and (in some cases) even death.

I don’t say that lightly.

In this article I want to go through 7 of the best cold weather sleeping bags ranging from sub-zero, bone-chilling cold to barely sub-freezing conditions.

And not only that, I want to show you how to choose the best cold weather sleeping bag based on factors specific to you:

• Your style of camping
• Your needs
• Your price range

There are thousands of different sleeping bags on the market, so let’s cut through the crap and get straight to the best of the best.

This is The Outdoor Authority’s Guide to the Best Cold Weather Sleeping Bags.

Skip the “How to Choose” and go straight to the best cold weather sleeping bags!

How to Choose the Best Cold Weather Sleeping Bag

Choosing the best cold weather sleeping bag is about more than just Temperature Rating. As you shop for the sleeping bag that’s best for you, consider these 6 factors:

1. Temperature Rating
2. Insulation Material
3. Sleeping Bag Shape
4. Zipper Design & Location
5. Weight
6. Additional Features

Let’s expand upon each.

Related: 13 Types of Sleeping Bags: The Most Complete Guide on the Internet

Temperature Rating

Sleeping bags are rated for temperature using a standardized process outlined in either EN 13537 or ISO 23537.

What is this process?

Essentially, a manikin rigged with thermal sensors is used in a controlled environment to rate the insulation power of a sleeping bag. Because a standard process is used every time, sleeping bags rated according to either EN 13537 or ISO 23537 criteria can be compared apples to apples.

Note: ISO 23537 became the standard in 2016. Prior to that, the standard was EN 13537. If you’re researching cold weather sleeping bags and come across EN 13537 ratings, note that it’s a similar and still useful rating.

These processes rate 3 different temperature limits for sleeping bags:

• Comfort Temperature: Lower limit of the comfort range for a sleeper in a relaxed position
• Limit Temperature: Lower limit of comfort range for a curled up sleeper
• Extreme Temperature: Lower limit for survival; the sleeper will feel cold but will survive

When you’re shopping for the best cold weather sleeping bag, you want to make sure the coldest weather you’d likely run into is above the Limit Temperature for the sleeping bag. Ideally it’s above the lower end of the Comfort Temperature range.

If there’s even a remote chance the temperature could drop below the Limit Temperature for a sleeping bag, you don’t want to buy that sleeping bag.

In the event that a sleeping bag doesn’t have a specific temperature rating, it probably has a general classification such as “Summer” or “3-Season.” If that’s the case, REI has a guide that can be used to turn those vague terms into approximate temperature ranges:

• Summer: Above 35°F
• 3-Season: 10°F-35°F
• Winter: Under 10°F

Note that the low end of these ranges is the Limit Temperature as defined above.

Insulation Material

Sleeping bag insulation can be made of two different materials:

• Synthetics, generally polyester
• Down feathers, generally duck or goose (duck is better)

While both are capable of keeping you warm, there are some key differences between the two.

Benefits of Synthetic Sleeping Bags

• Dry more quickly
• Non-allergenic
• Better insulation in wetter conditions (usually)
• Usually less expensive

Benefits of Down Sleeping Bags

• High-quality down bags can be much lighter for the same temperature rating
• Compress more easily
• Better insulation in dry conditions
• Longer lifespan when treated well

For more detail check out our Synthetic vs Down Sleeping Bag comparison, as well as our Last Guide You’ll Ever Need for Down vs Synthetic Insulation.

Sleeping Bag Shape

Sleeping bags come in 4 different shapes:

• Rectangular
• Semi-rectangular (ends taper inwards)
• Mummy
• Double-wide (rectangular for two people)

The first three descend from most comfortable/spacious to least comfortable/spacious. However, spaciousness is inversely proportional to insulation power. That means the best cold weather sleeping bag probably will be a mummy sleeping bag.

Zipper Design & Location

The zipper is the weak point in a sleeping bag. That’s where the insulation tapers off, giving way to a potential avenue for warm air to escape. As you look for the best cold weather sleeping bags, take a long look at the zipper. You’ll want to focus on three aspects of the zipper:

• Durability and quality of construction
• Length
• Location

Durability and quality are important (obviously) because a well-designed, well-made zipper will allow less warm air to escape and is much less likely to break. A stuck zipper that won’t properly seal your sleeping bag is a recipe for disaster.

Length is important because shorter zippers reduce the risk of warm air escaping. Many mummy style sleeping bags feature half-zip zippers with fully-enclosed feet. However, the downside to these types of sleeping bags is a lack of temperature regulation in warmer temperatures. You can’t just stick your feet out to cool down.

Location isn’t quite as important on a cold weather sleeping bag unless you want to connect two sleeping bags to make one larger sleeping bag. In this case, you’ll want to choose one left-handed zipper bag and one right-handed zipper bag, making sure the zippers are the same length. Note that the major downside here is you likely lose some insulation power. However, having shared body heat can mitigate that.

Weight

Weight is more about you being able to carry the sleeping bag on your pack if you’re backpacking. Heavier sleeping bags are not warmer by default. Remember that down vs synthetic discussion above? Synthetic sleeping bags actually weigh more for the same insulation power.

If you’re looking to cut weight, mummy sleeping bags should be given strong consideration. They’re narrower and use less material with the trade-off being their restrictiveness. Semi-rectangular sleeping bags will have more weight but also be more comfortable.

7 Additional Features on Cold Weather Sleeping Bags

As you’re shopping for the best cold weather sleeping bag, consider these additional features:

Hood With Drawstring // Extreme cold weather sleeping bags often have a constricting head design with a drawstring, giving you the ability to really seal yourself in.

Baffles // Baffles are designed pockets of insulation and are intended to keep insulation in specific areas. You can see these as the geometric stitching/seams visible from the outside of the sleeping bag. They’re especially important in down sleeping bags, as down feathers tend to shift more than synthetic polyester.

Face Mufflers // Face mufflers are baffles around the face that localize insulation to keep you warmer.

Pockets // Whether it’s tents, backpacks, or sleeping bags, pockets are a huge part of your camping and survival gear. Consider pocket location in your sleeping bag (if applicable). This is more important in restrictive mummy sleeping bags, as pockets near your hands to store your phone or flashlight can be especially helpful.

Related: 7 Best Survival Tents for EVERY Type of Hiker

Footbox Shape // Also more important in mummy sleeping bags, does the footbox round off the end or have a boxier, trapezoidal shape? A trapezoidal footbox provides a more natural shape for your feet, providing more comfort and potentially placing less stress on the sleeping bag material because your feet aren’t abnormally crammed inside. The downside, however, is more material/weight.

Sleeping Pad Compatibility // Some sleeping bags are “bottomless” in design, by which I mean they don’t have insulation on the bottom. Instead, they have either a sleeve or hooks where a sleeping pad slides in or attaches. The major upside to these sleeping bags is they’re lighter and store away more compactly. If you’re bringing a sleeping pad anyway, you may want to consider one of these sleeping bag designs.

7 Best Cold Weather Sleeping Bags

Without further ado, here are the 7 best cold weather sleeping bags ordered from most to least warm.

Big Agnes Crosho UL -20 Down Sleeping Bag

Best For: Lightweight, minimalist backpacking in the coldest of conditions

• Shape: Mummy
• Fill Type: Water resistant duck down
• Fill Power: 850
• Low-End Comfort Temp: -20°F
• Outer Shell: Nylon
• Inner Lining: Nylon taffeta
• Bottom Design: Insulated; no sleeping pad compatibility
• Footbox: Trapezoidal
• Weight: 3 lb (regular) | 3 lb, 4 oz (long)
• Fits Up To: 60″ (regular) | 62″ (long)

The Big Agnes Crosho UL -20 is an ultralight bag, giving it an unparalleled warmth-to-weight ratio compared to the other cold weather sleeping bags on this list. Take a look at the next sleeping bag on this list — the Elk Park -20 Synthetic, also by Big Agnes. That bag weighs a whopping 7 lb, 4 oz! This Crosho UL? Half that.

The baffles on this sleeping bag run vertically, parallel with your body, to contour closely with your body and seal in heat. However, you will need a sleeping pad below you to ensure comfort in sub-zero temperatures. The Big Agnes Two-Track Sleeping Pad is also rated to -20°F and and weighs as little as 1 lb, 8 oz.

Big Agnes Elk Park -20 Synthetic Sleeping Bag

Best For: Taller, bigger campers or those who want more room to move around inside the sleeping bag; campers venturing into wetter environments; anyone looking for extreme warmth for a lower price

• Shape: Mummy
• Fill Type: Synthetic
• Fill Power: N/A
• Low-End Comfort Temp: -20ºF
• Outer Shell: Nylon
• Inner Lining: Cotton/polyester
• Bottom Design: No insulation; sleeping pad sleeve
• Footbox: Trapezoidal
• Weight: 7 lb, 4 oz
• Fits Up To: 66″

If you need an extreme cold weather sleeping bag but don’t want to pay a premium for down, the Big Agnes Elk Park -20 synthetic sleeping bag is for you. As a synthetic sleeping bag it has some notable differences compared to the -20F Big Agnes Crosho UL above.

• Weighs a lot more
• Doesn’t pack away as compactly
• Performs better in wetter environments
• Doesn’t have an insulated bottom
• Costs a lot less

This Elk Park -20 also has more internal volume than the Crosho UL -20, making it ideal for bigger individuals who need a little extra room. And chances are, if you’re one of these larger individuals, you may not feel the added weight as much while carrying it.

Of note from that list above is that the Elk Park -20 doesn’t have an insulated bottom. Instead, it has a 25″ sleeping pad sleeve that’s compatible with the Wide Long Big Agnes Two-Track Sleeping Pad. That adds more weight, meaning you’re looking at a combined 9 lbs of sleeping gear.

Big Agnes Beryl SL 0 Down Sleeping Bag

Best For: Campers looking for a high-quality, compact cold weather sleeping bag for temperatures north of 0°F

• Shape: Mummy
• Fill Type: Water-resistant duck down
• Fill Power: 650
• Low-End Comfort Temp: 0ºF
• Outer Shell: Nylon
• Inner Lining: Nylon tafetta
• Bottom Design: No insulation; attachable sleeping pad sleeve
• Footbox: Rounded
• Weight: 3 lb, 2 oz (regular) | 3 lb, 5 oz (long)
• Fits Up To: 60″ (regular) | 62″ (long)

Yet another Big Agnes sleeping bag! (Hey, they make great stuff.) This Big Agnes Beryl SL 0 down sleeping has a Comfort Temperature down to 0°F but isn’t advised for use below that.

Like the Elk Park -20 above, the Beryl SL 0 requires a compatible sleeping pad. But instead of a sleeve attached to the sleeping bag, it features clips that allow you to attach the REM Pad Sleeve, into which you put your sleeping pad.

This REM Pad Sleeve comes with your Beryl SL 0 and doubles as a storage sack for the sleeping bag. The sleeping pad is sold separately.

With the detachable sleeping pad system, the Big Agnes Beryl SL 0 works over a wide range of temperatures. And with its lower fill power duck down and lighter weight, it packs away compactly.

In my opinion, this is the best 0 degree sleeping bag.

Nemo Sonic 15 Down Sleeping Bag

Best For: Minimalist camping in sub-freezing (but not sub-zero) temperatures

• Shape: Mummy
• Fill Type: Water-resistant duck down
• Fill Power: 850
• Low-End Comfort Temp: 15°F
• Outer Shell: Nylon
• Inner Lining: Nylon
• Bottom Design: Insulated; no sleeping pad compatibility
• Footbox: Rounded
• Weight: 2 lb, 10 oz (regular) | 2 lb, 14 oz (long)
• Fits Up To: 60″ (regular) | 66″ (long)

Finally, a sleeping bag by someone other than Big Agnes. The Nemo Sonic 15 down sleeping bag doesn’t have a Comfort Temperature as low as the Big Agnes Beryl SL 0 above, but it uses higher power duck down and weighs less.

What’s most notable about this sleeping bag is the venting system along the top sides, which prevents your body from overheating in warmer temperatures. (These aren’t visible in the thumbnail shown above but can be seen clearly in this video.)

The Sonic 15 also is rather spacious inside compared to other mummy sleeping bags.

If you’re planning on camping in temperatures under 20°F, you’re probably going to be pushing the limits of what this bag can handle. In this case, I’d recommend a sleeping pad and a well-designed tent. But for temperatures ranging from 20°F and above, the Nemo Sonic 15 is an awesome option with quality materials and super low weight.

Marmot Trestles 20 Synthetic Sleeping Bag

Best For: Campers looking for a lower price point while still getting slightly sub-freezing temperature performance

• Shape: Mummy
• Fill Type: SpiraFil synthetic fibers
• Fill Power: N/A
• Low-End Comfort Temp: 24°F
• Outer Shell: Polyester
• Inner Lining: Polyester
• Bottom Design: Insulated; no sleeping pad compatibility
• Footbox: Rounded
• Weight: 3 lb, 6 oz (regular) | 3 lbs, 11 oz (long)
• Fits Up To: 60″ (regular) | 66″ (long)

The Marmot Trestles 20 is a similarly temperature rated sleeping bag compared to the Nemo Sonic 15 above, but it’s a heavier option with synthetic insulation. Specifically, the insulation are Marmot’s SpiraFil synthetic fibers. They’re lightweight (by synthetic standards) and warm.

And as a synthetic sleeping bag, you can find it in a lower price range.

Despite the Marmot Trestle 20’s name, the lower limit of the Comfort Temperature isn’t 15°F. It’s 24°F. Frankly, it just isn’t as good as the Nemo Sonic 15 above, and I’d argue its performance isn’t much better than the Nemo Moonwalk 30 below.

Nemo Moonwalk 30 Down Sleeping Bag

Best For: Cold weather camping but not the coldest weather camping

• Shape: Semi-rectangular
• Fill Type: Water-resistant duck down
• Fill Power: 700
• Low-End Comfort Temp: 30°F
• Outer Shell: Nylon
• Inner Lining: Nylon
• Bottom Design: Insulated; no sleeping pad compatibility
• Footbox: Rounded
• Weight: 2 lb, 2 oz (regular) | 2 lb, 5 oz (long)
• Fits Up To: 60″ (regular) | 64″ (long)

I debated whether or not to put a 30°F sleeping bag on this list of the best cold weather sleeping bags. I mean, this isn’t an extreme cold weather sleeping bag, but 30°F is still cold and I wanted to give you an option at the upper end of the sub-freezing range.

Enter the Nemo Moonwalk 30 down sleeping bag. Its 700 fill power duck down doesn’t have the insulation strength of the 850 fill power down used in most of the sleeping bags above, but it weighs less and tucks away more compactly.

But perhaps the biggest difference between every other sleeping bag on this list is its shape: this is not a mummy sleeping bag! It’s actually semi-rectangular sleeping bag, but it still features a drawstring around the neck to reduce the heat that escapes.

Actually, there’s another huge difference: the Nemo Moonwalk 30 comes with its own tub-style bottom. This seriously cool design lets you sleep directly on the ground on a slightly elevated platform. It seems like a small thing to add, but it’s surprisingly comforting when you have it.

Patagonia Hybrid Down Sleeping Bag

Best For: Backpackers looking for extreme minimalism

• Shape: Mummy
• Fill Type: Water-resistant goose down
• Fill Power: 850
• Low-End Comfort Temp: Varies (see below)
• Outer Shell: Nylon
• Inner Lining: Nylon
• Bottom Design: Insulated; no sleeping pad compatibility
• Footbox: Trapezoidal
• Weight: 1 lb, 1 oz (regular) | 1 lb, 3 oz (long)
• Fits Up To: 60″ (regular) | 66″ (long)

The Patagonia Hybrid down sleeping bag is unlike any other sleeping bag on this list because they actually remove insulation around the upper half of your body in an attempt to cut weight. Seriously, look at that weight above.

One pound?

The blue upper half of this mummy-style sleeping bag actually has very little insulation. Instead, you’re supposed to wear a parka with it to keep your upper half warm. (Patagonia recommends the Grade VII Down Parka.) When you think about it, this is sort of ingenious. You already have a cold weather jacket. Why not use it with your cold weather sleeping bag?

The question then becomes, “How extreme can the cold be when using this sleeping bag?”

When combined with the proper down jacket, you can use this sleeping bag in conditions as low as 10-20°F. I wouldn’t really risk it beyond that unless you have a really good down parka.

Do you own a cold weather sleeping bag? Want to weigh in on which you think is the best? Comment below!