The Best Winter Sleeping Bags in 2021

We may receive commissions when you buy through links on our site. Learn more.

Are you looking for a cold weather sleeping bag that will keep you warm?

We are happy that you have found us during your search.

Cold weather camping involves purposeful preparations. You must have your gear rated to low temperatures to keep yourself comfortable, warm and, safe.

So, how do you guarantee this when you purchase a winter sleeping bag?

  • Temperature rating. You need one to be rated for a temperature of 15°F or lower.
  • Insulation materials. The two most common include down and synthetic. Depending on their fill level, they insulate and add comfort.
  • Packed size. Winter camping involves a lot more bulk. Be prepared to add a lot of poundage to keep yourself safe in the cold winter conditions.

Read More : 9 Things to Know Before Buying Winter Sleeping Bags

Look through our best winter sleeping back picks to find the perfect match. Pay attention to any gender specifications to find a snug fit.

Here are the 10 best winter sleeping bags.

Sleeping Bag ModelTemp. RatingWeight
REI Co-op Magma 15 16°F1.8lbs / 799g
Western Mountaineering UltraLite20°F1.8lbs / 822g
Kelty Cosmic 2020°F 2.4lbs / 1.1kg
Marmot Trestles Elite Eco 0 2.3°F 3.5lbs / 1.6kg
Mountain Hardwear Bishop Pass 00°F 3.1lbs / 1.4kg
Sea to Summit Ascent AcIII 00°F 2.9lbs / 1.3kg
NEMO Sonic 00°F3.0lbs / 1.4kg
The North Face Inferno -2020°F3.3lbs / 1.5kg
Therm-a-Rest Polar Ranger -2020°F3.3lbs / 1.5kg
Mountain Hardwear Phantom -40-40°F 4.6lbs / 2.1kg

REI Co-op Magma 15

REI Co-op Magma 15 Winter Sleeping Bags
Photo Credit : REI
  • Temperature Rating : 16°F / -8.9°C
  • Fill Material : 850-fill-power goose down
  • Weight : 1.8lbs / 799g

The REI Co-op Magma 15 is a wonder with one of the highest warmth-to-weight ratios. Hiking ultralight during the winter tends to be a challenge. This sleeping bag helps you to achieve that.

Men’s and women’s varieties are offered with this sleeping bag. The women’s form has extra hip room and less shoulder room. Improving the bag’s thermal efficiency of the bag is part of these changes, versus the extra shoulder room for men.

Both bags have plenty of knee and foot space for different positions without decreasing efficiency. The foot box has a trapezoidal shape, and the baffle points downward.

The materials are a water-resistant 850-fill-power goose down with a 15D lining and a Downproof Pertex shell. They have used a new snag-free zipper design and a hybrid path for easy access.

The hood is contoured and has space for a pillow with drawcords to hold in the head. Its design seems to be both a blessing and a curse, depending on your sleeping preferences.

A stuff sack and a mesh sack come with the REI Co-op Magma 15 for packing or breathable storage.

What We Like

  • Men’s and women’s sleeping bag varieties.
  • Thermal efficient design is considered in each part of the sleeping bag.
  • High warmth-to-weight ratio compared to other winter sleeping bags.

What We Don't Like

  • Hood is relatively poorly designed without many options.

Western Mountaineering UltraLite Sleeping Bag

Western Mountaineering UltraLite Winter Sleeping Bags
Photo Credit : Western Mountaineering
  • Temperature Rating : 20°F / -6.7°C
  • Fill Material : 850+ fill-power-down
  • Weight : 1.8lbs / 822g

Western Mountaineering offers another option for a sleeping bag with a high warmth-to-weight ratio. It is a good fit for ultralight winter backpacking in chilling temperatures. Insulated with down, the bag gets heavy if wet.

Versatility is the name of the game with a sleeping bag. This is especially true if you plan to camp in borderline temperatures. The fill keeps it comfortable during freezing nights while it can still be configured to be more breathable.

An ExtremeLite shell with a high thread count makes it smooth and soft to the touch. The lining is extra soft nylon taffeta, a bonus at the end of the long day of trekking.

Interlocking draft collars stop heat loss, mostly around the neck and shoulder gap. The girth at the shoulders is a bit more narrow to insulate further with pockets of dead air.

Western Mountaineering makes its UltraLite sleeping bags in the USA. They include a stuff sack to compress the bag and increase its packability.

What We Like

  • ExtremeLite shell fabric insulates without weight.
  • High warmth-to-weight ratio compared to similar items.
  • Collar design for extra warmth.

What We Don't Like

  •  Higher price compared to other similarly rated sleeping bags.

Kelty Cosmic 20

Kelty Cosmic 20 Winter Sleeping Bags
Photo Credit : Kelty Cosmic
  • Temperature Rating : 20°F / -6.7°C
  • Fill Material : CirroLoft synthetic insulation
  • Weight : 2.4lbs / 1.1kg

Kelty creates their Cosmic 20 sleeping bag in both a men’s and women’s variety for increased warmth. The changes are based on the different areas that men and women tend to lose more heat. As a contrast to the down sleeping bags above, the Kelty Cosmic features synthetic insulation.

If you want a sleeping bag for ultralight camping, this might not be at the top of your list due to its size. However, for a warm weekend or car camping trip, this is one of the best synthetic sleeping bags.

This sleeping bag is finished with an eco-friendly treatment of DWR (Durable Water Repellent) and keeps insulating even in wet conditions. The draft collar is adjusted with a drawcord. A three-quarter zipper is accessible and stops heat from escaping.

High-quality and well-placed seams are essential for a winter sleeping bag. On the Kelty Cosmic 20, the seams are ground-level along the sides for extra durability and warmth. A stuff sack is included for increased packability, down to 8” x 15.5”.

What We Like

  • Men’s and women’s variety is offered for gender-specific warmth.
  • DWR treatment is eco-friendly and warm in wet weather.
  • Ground-level side seams increase durability and warmth.

What We Don't Like

  • Increased weight makes it a better choice for car campers.

Marmot Trestles Elite Eco 0

Marmot Trestles Elite Eco Winter Sleeping Bags
Photo Credit : Marmot Trestles
  • Temperature Rating : 2.3°F / -16.6°C
  • Fill Material : HL-ElixR Eco Micro synthetic recycled fibers
  • Weight : 3.5lbs / 1.6kg

Looking for something that can handle a deep freeze? Search no further than the Marmot Trestles Elite Eco 0.

The HL-ElixR Eco Micro insulation is key to their warm recipe in this bag. It blends three different types of fiber to gain a high loft, keep you toasty, and retain softness. Compressibility isn’t lost with this bag, either, with a stuffed size of 9.5” x 21”, larger than most but admirable for such a low-rated bag.

With a lining made of 20D recycled ripstop polyester, the bag is still soft to the touch. It is in a mummy shape with an anatomic 3D foot box. The 3D adjustable hood keeps the shoulders warm.

If you are worried about the versatility of the sleeping bag, you can stop right there. There is the main zipper with an anti-snag slider, but a secondary zipper increases ventilation and accessibility.

Marmot’s Trestles Elite Eco 0 is equipped with hang loops for transport, an internal stash pocket, and a stuff sack and storage bag.

What We Like

  • Secondary zipper for higher breathability.
  • 3D hood and foot box increase heat retention and comfort.
  • Design additionals include hang loops and stash pockets.

What We Don't Like

  • Compressibility is not low enough for most backpackers.

Mountain Hardwear Bishop Pass 0

Mountain Hardwear Bishop Pass 0 Winter Sleeping Bags
Photo Credit : Mountain Hardwear
  • Temperature Rating : 0°F / -17.8°C
  • Fill Material : 650-fill-power fluorine-free down
  • Weight : 3.1lbs / 1.4kg

Another bag with a down fill never goes amiss. This sleeping bag from Mountain Hardwear is certified to the Responsible Down Standard. Performance Plus Mummy cut makes it fit closely to the body for increased warmth while still offering enough wiggle room to move around at night.

20-denier ripstop nylon makes up the shell with a sustainable DWR treatment to stay warm even in wet weather. An exciting addition to this bag is the glow-in-the-dark zipper to make it easy to access no matter the time of day. It also features an anti-snag slider and a 2-way feature to increase ventilation.

A shaped draft collar adjusts tightly to keep in your body heat. For those bone-chilling nights out, use the adjustable down-filled face gasket and take full shelter.

Hang loops come sewn onto the Mountain Hardwear Bishop Pass 0 sleeping bag to make it easier to transport. Use the internal stash once you are zipped in and snug to store small essentials. It also comes with a stuff sack and a storage bag.

What We Like

  • DWR treatment keeps you warm in wet weather.
  • Down-filled face gasket increases heat retention.
  • Hang loops sewn in for easier transport.

What We Don't Like

  • Drawstring cord not easily accessed from inside.

Sea to Summit Ascent AcIII 0

Sea to Summit Ascent AcIII 0 Winter Sleeping Bags
Photo Credit : Sea to Summit
  • Temperature Rating : 0°F / -17.8°C
  • Fill Material : 750-fill-power UltraDry Down
  • Weight : 2.9lbs / 1.3kg

Choose between the regular and extended varieties of this bag to increase your comfort, no matter the heat. Instead of a mummy form, the bag has a tapered rectangular shape to give you space and warmth.

As is typical with sleeping bags rated this low, the foot box has an anatomical shape. Vertical chest baffles keep the down where they should be to insulate the right areas. A large hood with drawcords gives you space but the possibility for warm shoulders when drawn tight.

Lightweight 20D nylon makes up the shell and lining fabrics of this bag. On the right side, there is a free-flow half-zip, and on the left side a 2-way full-length zip. The combination allows you to maximize ventilation and also use it as a quilt.

Buying the Sea to Summit Ascent AcIII 0 also gives you a compression bag and a large internal pocket.

What We Like

  • Tapered rectangular shape increases warmth and space.
  • Internal storage pocket keeps small items secure.
  • Unique zipper construction means more versatility.

What We Don't Like

  • Narrow girth for some considering tapered shape.

NEMO Sonic 0

NEMO Sonic 0 Winter Sleeping Bags
Photo Credit : NEMO
  • Temperature Rating : 0°F / -17.8°C
  • Fill Material : 800-fill-power hydrophobic down
  • Weight : 3.0lbs / 1.4kg

Nemo uses a hydrophobic down, meaning it is extra water-resistant even compared to other naturally resistant downs. The Nemo Sonic 0 sleeping bag is also certified by the Responsible Down Standard to ensure the humane treatment of the animals.

A Toester foot box keeps the feet area breathable and waterproof. The shell fabric is created with a 20D ripstop nylon fabric and 30D nylon taffeta lining treated with DWR to keep the moisture out.

NEMO redesigned the collar with a zipper draft tube to give you an extra barrier. Their zipper is uniquely offset to seal in your heat. From top to bottom, the design of Nemo Sonic 0 sleeping bag is intentional.

A contoured hood with a drawstring keeps in the heat on top while the foot box features an extra layer of insulation and in the middle, stretch construction for knee movement.

What We Like

  • Hydrophobic down insulation offers more moisture control.
  • Toester foot box has an extra layer of insulation.
  • Stretch knee construction for greater movement.

What We Don't Like

  • Toester footbox can be too hot for some warmer sleepers.

The North Face Inferno -20

The North Face Inferno -20 Winter Sleeping Bags
Photo Credit : The North Face
  • Temperature Rating : -20°F / -28.9°C
  • Fill Material : 800-fill-power ProDown
  • Weight : 3.3lbs / 1.5kg

North Face has engineered their Inferno -20 for mountaineering, which often features expeditions with the coldest temperatures. 800-fill ProDown is enhanced with a hydrophobic finish for increased heat in wet weather. It is said to repel moisture for up to 10x longer than untreated down.

A mummy shape keeps the bag tight to the sleeper with a generous top cut for those with wider shoulder girths. All over the bag, the fabric is augmented with water-resistant Neovent Air fabric, on the hood, back, and foot box.

The specialized design of the sleeping bag includes a trapezoidal side baffle to keep the down in place, a full draft collar with an overlap to prevent heat loss, and a focused foot box.

Center zippers aren’t very common, but The North Face believes it makes the Inferno -20 easier to access. Unfortunately, it is not anti-snag equipped. Once zipped up, use the internal pocket for storage. In the morning, use the compression sack for a quick pack.

What We Like

  • Hydrophobic finish repels moisture for 10x longer.
  • Neovent Air fabric keeps insulation dry.
  • Compression sack included.

What We Don't Like

  • No anti-snag device on the center zipper.

Therm-a-Rest Polar Ranger -20

Therm-a-Rest Polar Ranger -20 Winter Sleeping Bags
Photo Credit : Therm-a-Rest
  • Temperature Rating : -20°F / -28.9°C
  • Fill Material : 800-fill-power goose Nikwax Hydrophobic down
  • Weight : 3.3lbs / 1.5kg

Therm-a-Rest has created its own version of a mountaineering sleeping bag. Rated to -20°F and just over 3lbs, it packs down to 11” x 20”. It is a unisex bag complete with a down certification to the Responsible Down Standard.

From bottom to top, Therm-a-Rest strives to make their bag as ergonomic as possible. A snorkel hood at the top controls frost and draft entry. Along the sides, there are overlapping vents to allow arm usage and give you customizable temperature control if it isn’t quite as cold. When it is cold, the overlapping draft tubes stop cold spots when you are zipped in.

There are connectors attached to the bag to integrate it with a mattress for comfort optimization. What’s more, quilt and blanket loops give it greater attachability. At the bottom, the baffled toe pocket keeps your feet warm.

Therm-a-Rest Polar Ranger -20 has a shell fabric of ripstop polyester with a DWR treatment. Hydrophobic down insulation dries 3x as fast as untreated down. For packability, a compression and storage sack are included.

What We Like

  • Side vents to keep it cool on warmer nights.
  • Connectors and loops for easy integration.
  • Hydrophobic down dries 3x as fast as untreated.

What We Don't Like

  • Packs down to a large size.

Mountain Hardwear Phantom -40

Mountain Hardwear Phantom -40 Winter Sleeping Bags
Photo Credit : Mountain Hardwear
  • Temperature Rating : -40°F / -40°C
  • Fill Material : 850-fill-goose down
  • Weight : 4.6lbs / 2.1kg

Mountain Hardwear went the extra mile with their Phantom -40. It is our lowest-rated sleeping bag, as well as the heaviest. This is one of the best cold weather sleeping bags for those ready to take on a polar adventure. Otherwise, the weight doesn’t make it worth it to haul around.

Goose down is used in this sleeping bag instead of duck. It has Gore Windstopper shell fabric, a specially engineered 30D ripstop nylon that is 100% windproof and moisture blocking.

An expedition mummy cut gives the sleeper some extra girth for more positions. Get in and out easily with a durable anti-snag zipper that glows in the dark. Tuck stitching only increases that durability, protecting the baffle stitches throughout the bag from abrasion.

At the top, there is a shaped, down-filled draft collar to prevent warm air from escaping. The Phantom -40 sleeping bag also includes a face gasket to cinch up on the coldest of nights. At the bottom, a 3D anatomical foot box keeps in warmth and exceeds comfort expectations.

What We Like

  • Temperature rating extremely low.
  • Gore Windstopper keeps out wind and moisture.
  • Anti-snap zipper glows in the dark.

What We Don't Like

  • Heavy-weight for anyone other than mountaineers.

Winter Sleeping Bags Buying Guide

Even among winter sleeping bags, there are specifics to think about regarding your specific situation. Make sure you understand temperature ratings, sizes, and weights before buying it and setting out on your next frigid adventure.

Here are 9 things to think about before you buy a winter sleeping bag.

Temperature Rating 15ºF or lower

Sleeping bags fall into three primary categories when considering their appropriate seasonal usage. There are the

  • Summer season, rated 30°F+.
  • 3-seasons (shoulder seasons), rated from 15°F to 30°F.
  • Winter season, which is 15°F and lower.

What do these ratings really mean, though?

How do they compare to your needs?

  • Upper limit. Almost all sleeping bags, especially winter ones, have three ratings. The upper limit is not a standard measurement. It gauges how warm is too warm to use the bag in. Winter sleeping bags have a lot of extra insulation, and using them without proper ventilation in other seasons can cause you to overheat.
  • Comfort. The comfort rating is often not the one advertised. For example, the Marmot Trestles Elite Eco 0 is advertised with the lower limit in mind, 2.3°F, but its comfort rating is 15.6°F. That is a big leap. Unless a sleeping bag has men’s and women’s varieties, the lower limit is meant for men and the comfort for women, who tend to lose heat faster. If you are a cold sleeper, find a bag with a comfort limit that appeals to you, not the lower limit.
  • Lower limit. The lower limit applies to warmer sleepers. It is the temperature that is safe to use the bag in. The REI Co-op Magma 15 is at the top of the winter bag spectrum and the Mountain Hardwear Phantom -40 is at the bottom. The lower the limit often means the higher the weight.

Read More : What Does Sleeping Bag Rating Means?

Down vs. synthetic insulation

As in all sleeping bags types, down and synthetic insulators are the most common.

In winter sleeping bags, down is more typical.

Down has a higher fill power rating. It is also more resilient to compression, gets better loft, and traps more air, giving it better insulation power.

The Marmot Trestles Elite Eco 0 uses a synthetic material for its insulation as does the Kelty Cosmic 20 sleeping bag. However, these are some of the few.

Down tends to be heavier, so it isn’t as common in summer and 3-season bags. Most winter trekkers and mountaineers accept the extra weight of down for the other characteristics necessary in frigid temps.

Read More : Down vs Synthetic Insulation – Which One Is Better?

Down fill power

The down fill power is a unit that measures the loft of down, aka its fluffiness. It is related to its insulating power. The higher the fill power signifies the increased amount of air, the down can trap inside. The more air equals the more insulating ability the down has.

Most winter sleeping bags need at least an 800-fill-power down.

Over time, this does decrease with use. However, starting with a higher number means increased longevity for the sleeping bag.

Western Mountaineering UltraLite sleeping bag has an 850+ down fill power even with a weight under 2lbs. Therm-a-Rest Polar Ranger -20 has an 800 goose down fill power, yet it is rated so much lower. The comparison makes a great example of the importance of focused engineering for the rest of the sleeping bag outside of the insulation.

Read More : Guide to Down Fill – Here’s How Much You Really Need

Fit and comfort

If you are warm at night but feel trapped and uncomfortable, does it even matter? 

A comfortable sleeping bag is created to focus on three main factors; the loft, the ventilation, and the cut.

  • Loft of a sleeping bag again relates to its fluffiness. Many winter sleeping bags are equipped with more insulation along the bottom to increase the space between you and the cold ground.
  • Ventilation in a low-rated sleeping bag maximizes its versatility. You should be able to open side vents or uncinch the top to increase airflow in warmer temperatures. An example is the Mountain Hardwear Bishop Pass 0, with a two-way zipper.
  • Shape. A sleeping bag can take many shapes, primarily mummy and tapered rectangular, such as the Sea to Summit Ascent AcIII 0. These curves with the general shape of your body. If you are especially wide in the shoulders or the hips, pay attention to the bag’s measured girth in those areas.

Packed size and weight

The lower the temperature rating often equals a larger pack size and weight. Almost all sleeping bags come with a compression sack, but check out how small they go.

Ideally, you want a sleeping bag that packs down smaller, but it is typically around 10” to 14” x 17” to 22” and weighs 3lbs or more.

Water resistance

Another good reason many companies use down is its natural water resistance. However, it isn’t perfect and is made better through waterproofing treatments.

On synthetic materials, this is often a coat of DWR, Durable Water Repellent. The NEMO Sonic 0 has a nylon taffeta lining treated to keep the moisture from even reaching the down.

Down can also receive a treatment called a hydrophobic finish. Ensure it is safely treated without using PFCs. The treatment increases the water-resistance of the material exponentially, taking 10x as long to soak up moisture and drying out 3x faster than untreated down.

The North Face Inferno -20 is a great example of down with a hydrophobic finish.

Durability

Durability comes down to the strength of the fabric that is used and the strength of the seams. Anymore, most bags are created with a ripstop version of polyester or nylon. These are reinforced so that it is more difficult to puncture or tear the fabric.

Seams can come apart no matter the strength of the fabric and are often the other weak point of a sleeping bag. They can be doubled up to increase durability, or covered to stop abrasion over the top.

Read More :

Extra features

Not all winter sleeping bags are created equally. Each company likes to try and better the overall design. Some of them might add extra features so winter campers feel like it is more of a buy.

Some of these features include :

  • Hood. Most sleeping bags have some kind of head at the top, especially mummy bag options. A hood feature allows it to cinch around your head so that it keeps in the warmth around your face.
  • Interior pockets. Interior pockets add nothing but convenience. Keep your smaller belongings safe with you at night by inserting them into the pocket once you have zipped yourself inside.
  • Draft tubes. A draft tube runs along the zipper on the inside of the sleeping bag. It increases the insulation along with a weaker point of a bag.

Price range

More expensive materials are often those that are lightweight and compressible while still maintaining warmth. For as much as a backpacker might want this, sometimes it simply doesn’t fit into their budget.

There are still options for you, however.

  • Budget. If you look for something rated just under the 15°F mark, you can find options for $75 to $150. These are often quite large and may have a higher comfort level.
  • Average. The average price range for a winter sleeping bag is around $200 to $300. Their added insulation and increased technology within the materials make them more expensive than an average 3-season bag.
  • Premium. Bags that are rated very low and combine it with comfort are premium purchases. These can cost $700 to $1,500. Often, lightweight options fall into this category.

FAQ

Duck vs. goose down - which one is better?

Duck and goose down are quite similar. Since geese often live in colder environments, their down clusters are larger, which means a higher fill power. 

However, duck down doesn’t differ by much and is often cheaper than goose down. There is not enough of a difference, often, to make it worth it to spend more on a goose-down product.

What is the main difference between men vs. women sleeping bags?

The shape of the sleeping bag differs slightly. The girth of a women’s bag is wider in the hip area and slimmer across her shoulders. 

For a man, it is the opposite as their shoulders tend to be the widest parts of their body. Women’s bags focus insulation heavier in the areas where they lose heat more quickly as well.

Amanda Williams

Amanda Williams is a writer, plant-nerd, and outdoor enthusiast. She has traveled extensively, around the U.S., throughout Asia, Europe, and Latin America. Everywhere she treks, she takes time to enjoy the outdoors. John Muir is her hero. She aspires to inspire people to live better as he did.