A good sleeping bag is essential to ensure that you get your well-deserved sleep during your adventures – whether it’s a trip through South America, a trek in the Himalayas or a bike ride along the Balkan coast. The best mummy sleeping bags offer maximum protection from the cold while occupying the minimum amount of space when packed down.
Today, brands have developed new technologies to create extremely light and compact products, offering great comfort even at the lower temperatures. We have selected the five best mummy sleeping bags for every season, so you can go hiking anywhere without worrying about nighttime comfort.
For a complete analysis of all backpacking sleeping bags, check out the buyer’s guide Best Backpacking Sleeping Bags.
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Quick Answer - The Best Mummy Sleeping Bags
- Feathered Friends Hummingbird UL 20
- Big Agnes Sidewinder SL 20
- Kelty Cosmic 20
- Marmot NanoWave 45
- Western Mountaineering Alpinlite
Comparison Table - Best Mummy Sleeping Bag
For the best experience turn your device horizontally| Name | Insulation | Temp Rating | Weight | Price | Rating | Review |
|---|---|---|---|---|---|---|
| Feathered Friends Hummingbird UL 20 | Down | 20 F | 1.5 lbs | $539 | 4.9 | Read Review |
| Big Agnes Sidewinder SL 20 | D-S Blend | 20 F | 2.2 lbs | $280 | 4.7 | Read Review |
| Kelty Cosmic 20 | Down | 32 F | 2.6 lbs | $170 | 4.3 | Read Review |
| Marmot NanoWave 45 | Synthetic | 56 F | 1.8 lbs | $79 | 4.2 | Read Review |
| Western Mountaineering Alpinlite | Down | 20 F | 2.0 lbs | $585 | 4.9 | Read Review |
| Name | Insulation | Temp Rating | Weight | Price | Rating | Review |
Temp ratings refer to the EN or ISO Comfort rating.
Weight and price are shown for the regular size.
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Reviews - The Best Mummy Sleeping Bags for Backpacking
Feathered Friends Hummingbird UL 20
Specs
- Fill Weight: 14.6 oz
- Insulation: Down
- Length: 72 inches
- Weight: 1.5 lbs
- Shape: Mummy
- Volume: 09.0 L
- Temp Rating: 20 F
- Fill Power: 950
Features
- Trapezoidal footbox
- Continuous baffles
- 3D contoured hood
BEST ULTRALIGHT SLEEPING BAG
The Feathered Friends Hummingbird UL 20 is a super light and packable three season sleeping bag. It’s our pick for the best ultralight backpacking sleeping bag.
What we loved the most about the Hummingbird is the conservative, even borderline generous temperature rating. This is not something we could say about a lot of other ultralight bags out there. The Hummingbird is stuffed with 950+ goose down which makes it extremely warm and light.
One drawback of the Hummingbird is the fit is pretty snug. If you’re a side sleeper or a bigger guy or gal, you might find the narrow dimensions claustrophobic. If you toss and turn a lot and would prefer a more spacious bag, check out the Feathered Friends Swallow and Swift. Another downside is since Feathered Friends is a cottage manufacturer, stock can sometimes be limited and wait times can be long. If you love the idea of owning a handmade sleeping bag that is tailored to your needs, be sure to order well ahead of your next trip.
The Hummingbird UL is in close competition with Western Mountaineering’s UltraLite. which is also featured on this list. While both are excellent choices for serious backpackers, the Hummingbird is 5 ounces lighter, making it a winner for those who are meticulous about cutting weight.
The Hummingbird UL is also available in a 30-degree version.
Big Agnes Sidewinder SL 20
Specs
- Fill Weight: 19.0 oz
- Insulation: D-S Blend
- Weight: 2.2 lbs
- Volume: 04.3 L
- Temp Rating: 20 F
- Fill Power: 650
Features
- Body-mapped FireLine™ ECO synthetic insulation
- Made from post-consumer recycled polyester
- Includes storage sack and stuff sack
BEST SLEEPING BAG FOR SIDE SLEEPERS
The Big Agnes Sidewinder SL20 is spacious enough to be a game changer for side sleepers but it doesn’t trap cold air as much as other wide options.
What we love the most about the Sidewinder SL20 is that it’s one of the only bags on this list that is truly built for side sleepers. The zipper and the hood face the side. The insulation and shape are all geared toward those who roll over. There is a mesh pocket for your pillow that keeps it in place. There is extra padding at the hip and feet, which are two pressure points for those who tend to flip from side-to-side several times throughout the night. There is plenty of room to curl your knees up without feeling constricted as you might in a mummy bag.
One complaint we have with this bag is the zipper catches if you aren’t careful despite having an “anti snag zipper”. Maybe we were too rough with it but this could be annoying if you have to get up in the middle of the night. Also, people with wide feet might find the toe box a bit tight.
The Nemo Disco 15, which is also featured on this list is a close competitor to the Big Agnes Sidewinder SL 20. The Sidewinder gains points on weight (it’s 7 ounces lighter), but it is not as roomy as the Disco. The extra inches on the shoulders and hips are nice but you also have to consider that it’s not the best design for retaining warmth.
The Big Agnes Sidewinder SL 20 also comes in a women’s version.
Kelty Cosmic 20
Specs
- Fill Weight: 16.0 oz
- Insulation: Down
- Length: 72 inches
- Weight: 2.6 lbs
- Shape: Mummy
- Volume: 09.2 L
- Temp Rating: 32 F
- Stuff Sack Size: 8 x 13 inches
- Fill Power: 550
Features
- 550-fill down
- C0 and PFC-free durable water repellent (DWR) coating
- Internal zippered stash pocket
The Kelty Cosmic 20 is a budget minded down sleeping back that is a great option for new backpackers who don’t mind carrying a bit of extra weight and bulk to save some cash.
What we love the most about this bag is its overall value. The Cosmic’s quality and warmth are great considering how inexpensive it is. Of course, you can’t compare the build and material quality of the Cosmic to the top of the line bags on this list but it is practical and comfortable enough, making it tough competition for other budget options.
The biggest downside of the Cosmic is it is much more heavy and bulky than other backpacking sleeping bags, but hey, it’s one of the cheapest down bags around. If you’re just starting out, you could always go for the Cosmic and if you end up becoming a hiking junkie, you could upgrade and retire this bag to car camping adventures.
This bag is also offered in 40-degree and 0-degree versions.
Marmot NanoWave 45
Specs
- Fill Weight: 13.9 oz
- Insulation: Synthetic
- Length: 72”
- Weight: 1.8 lbs
- Shape: Mummy
- Volume: 05.0 L
- Temp Rating: 56 F
- Stuff Sack Size: 6x11”
- Fill Power: Spirafil
Features
- Snagless Draft Tube Keeps Cold Air From Seeping Through Zipper
- Zipper Wraps Around Foot Box For Easy Ventilation
- “Feely” Drawcords For Easy Adjustment Even In The Dark
- Synthetic Proprietary Insulation Traps Warmth Even When Wet
BEST BACKPACKING SLEEPING BAG UNDER $100
The Marmot Nanowave 45 is an affordable summer sleeping bag that won’t take up too much room in your backpack. Not only is it cheap, it’s practical and functional which is why it’s our pick for the best backpacking sleeping bag under $100.
In awarding it the winner of the best under $100 category, we realize it’s not quite fair because most other bags on this list have a temperature rating down to around 20 degrees. However, if you’re on a super tight budget and plan to camp from mid-spring to mid-fall, the Nanowave 45 is hard to beat.
Which leads us to the biggest downside of this bag, it is only good in mild weather. But, not everyone needs or wants a super warm bag and if you combine the Nanowave with an extra warm sleeping pad and a thermal liner, you might be able to extend the temperature range of this bag down a few degrees, making it much more versatile. If you’re looking for a warmer budget backpacking sleeping bag, check out the REI Trailbreak 20 which is also featured on this list.
Western Mountaineering Alpinlite
Specs
- Material: Nylon
- Fill Weight: 19.0 oz
- Insulation: Down
- Length: 6’6”/6’0”/5’6”
- Weight: 2.0 lbs
- Shape: Mummy
- Volume: 12.0 L
- Temp Rating: 20 F
- Fill Power: 850
- Compressed Volume: Approximately 12 Liters
- Shoulder Girth: 65/64/63in
Features
- Extra Wide Shoulder Girth For Bigger Hikers
- Very Comfortable And Warm Design
- Made In The U.S.A
BEST FOR: HIKERS WHO WANT MORE SHOULDER ROOM
Don’t you hate trying to roll over in your sleeping bag and your shoulders seem to get wedged between the upper and lower layers? Us too, and that’s why the AlpinLite is among the best 20 degree sleeping bags. This bag is designed with you broad chested hikers in mind to make sure you can sleep in comfort on every single hiking trip.
We’ve found the 63” to 65” shoulder girth to give just about everyone plenty of room to snuggle in and find that sweet spot for optimal sleeping. All other features of the AlpinLite are near identical to Western Mountaineering’s UltraLite sleeping bag. This bag is very comfortable due to its 850-fill down insulation nestled in a soft nylon shell. And it’s even manufactured in the U.S.A.
As with most products from Western Mountaineering, the AlpinLite comes with quite the pricetag. But it’s premium build quality, comfortable materials, and very roomy design easily make this a worthwhile investment for you serious hikers out there.
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THINGS TO CONSIDER WHEN BUYING THE BEST MUMMY SLEEPING BAGS
TEMPERATURE RATING
Summer sleeping bags have a rating of 37°F and up. They are often light in weight because they provide less insulation and are highly packable. These are usually the more basic models, meant to protect you from the wind, but not ideal in very cold environments.
Three-season sleeping bags are best suited for traveling in spring and autumn but can also be used in summer, especially if you plan to pitch your tent in the high mountains where nights can be freezing. These models have more functionality than the summer ones: they often have hoods and other features to fight the coldest temperatures. The rating of these multipurpose bags is usually between 20°F and 32°F.
Sleeping bags with a rating below 20°F are meant to keep you warm in any environment, even in the snow. They have all the characteristics of the three-season sleeping bags, with an added layer of insulation to ensure greater protection. These bags are normally bulkier and heavier, but essential if you plan to sleep in environments where temperatures drop heavily during the night.
INSULATION TYPE
Sleeping bags made of synthetic materials do not absorb water and offer excellent protection from soil moisture or light rainfall. These types of sleeping bags are relatively cheap, but they can be bulkier and heavier than down sleeping bags.
Down insulation made from duck or goose feathers is the lighter in terms of weight. These bags can be compressed to a smaller size than synthetic, and they offer the highest protection against the cold. Down sleeping bags are generally more expensive than their synthetic counterparts and do not offer insulation when wet.
WEIGHT
Any hiker knows how important it is to keep the pressure on their shoulders at a minimum, and therefore it is important to consider the weight of a sleeping bag before buying. Ultra-lightweight sleeping bags are best suited for backpacking, however, the reduced weight and bulk usually come at a high price. Summer sleeping bags are lighter than three-season and winter bags as they contain less insulating material, but consider the temperatures you’ll be sleeping at before looking at the weight you’ll be carrying.
PACKED VOLUME
When shopping for a sleeping bag, make sure you check how much space it will occupy in your backpack. Just because a sleeping bag is lightweight doesn’t necessarily mean it is also highly compressible. The volume of a compressed sleeping bag is measured in liters and you should aim at a maximum of 3 liters if your priority is reducing bulk.
FEATURES EXPLAINED
Draft tube
The part of the sleeping bag running along with the zippers that is filled with insulating material to reduce the risk of cold air entering.
Hydrophobic
A water-repellent material.
Duck or goose down
The soft plumage that ducks and geese hide under their feathers, used as the insulating material in sleeping bags to protect against heat loss.
Synthetic insulation
Polyester fibers employed as the insulating material to prevent heat loss. A cheaper alternative to down.
Sleeping bag shell
A sleeping bag’s outer layer, usually made of water-repellent nylon.
Snag-free zippers
Zippers designed so that they don’t catch the sleeping bag’s fabric when pulled.
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For more of our top hiking & backpacking gear recommendations, check out these popular buyer's guides:
Best Backpacking Sleeping Bags
Best Backpacking Sleeping Pads