Ultralight Winter-Worthy 0 degree sleeping bags
When temperatures drop well below freezing, you will need a 0 degree sleeping bag to achieve a good night’s rest. Three-season models rated 20-30F are not sufficient. In our experience, a 0 degree rating is the most well-rounded and usable from late fall through early spring, and comfortable for camping in temps ranging from 10-25F, depending on your personal warmth levels. To get the most use out a winter sleeping bag purchase, we recommend against choosing models in the sub-zero category unless you already have a 0 degree.
This is a data-based gear guide. We ditch subjective analyses like perceived warmth and scattershot backcountry testing. Instead we evaluate each 0 degree sleeping bag as neutrally as possible, primarily based on its uncompressed down volume per ounce of total weight stat. This measurement has a strong correlation to warmth-to-weight ratio, and allows us to assess which winter sleeping bag uses its mass to insulate most effectively. As such, we are very confident in our objectively selected assortment. Many popular models were excluded for inferior stats.
Complete your system with our guides to dry bags, winter sleeping pads, backpacking pillows, lightweight 4 season tents. Crank up the warmth-to-weight ratio with a 0 degree quilt. Add in a pair of backpacking booties, down pants, or a down parka.
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Lightweight 0 Degree Sleeping Bag Quick Picks
- Best Overall: Sea to Summit Spark 0
- Next Best: Western Mountaineering Kodiak MF 0
- Best Performance: Mountain Hardwear Phantom 0
- Best Ultralight & Best Value: Outdoor Vitals Summit Down 0
- Best Budget: Mountain Hardwear Bishop Pass 0
- Most Girth: The North Face Inferno 0
- Top Pick Lightweight: Therm-a-Rest Parsec
- Best Waterproof: Feathered Friends Snowbunting, Murre, Ibis
Lightweight 0 Degree Sleeping Bag Comparison Table
Mobile users rotate phone sideways for complete table view
| Model | Price ($) | Weight (oz) | Fill Weight (oz) | Fill Power | Down Vol (in³) | Down Vol/Total Weight (in³/oz) |
| Sea to Summit Spark 0 | 649 | 39.7 | 29.6 | 850 | 25160 | 640 |
| Outdoor Vitals Summit Down 0 | 430 | 35.0 | 25.8 | 800 | 20640 | 590 |
| Wstrn Mtnring Kodiak MF 0 | 835 | 44.0 | 30.0 | 850 | 25500 | 580 |
| Mountain Hardwear Phantom 0 | 680 | 42.4 | 30.5 | 800 | 24400 | 575 |
| The North Face Inferno 0 | 590 | 42.0 | 29.0 | 800 | 23200 | 552 |
| Therm-a-Rest Parsec 0 | 570 | 38.0 | 26.0 | 800 | 20800 | 547 |
| Feathered Friends Snowbunting 0 | 789 | 45.3 | 25.3 | 900 | 22770 | 528 |
| Mountain Hardwear Bishop Pass 0 | 325 | 50.0 | 33.0 | 650 | 21450 | 429 |
How To Read This Table
- Fill Weight: Measures in ounces the total weight of all down insulation used in the sleeping bag
- Fill Power: Measures in cubic inches the volume per ounce of uncompressed down
- Down Vol (in³): Measures the volume of all down in the sleeping bag if were to be extracted and put into an uncompressed pile. It is derived by multiplying fill weight times fill power. It strongly correlates with the insulative ability of a sleeping bag. If Sleeping Bag A has more Down Vol (in³) than Sleeping Bag B, it is extremely likely that Sleeping Bag A will feel warmer.
- Down Vol/Total Weight (in³/oz): Measures the uncompressed down volume in cubic inches per ounce of total sleeping bag weight (counting the shell fabric, zipper, trim, etc). This measurement strongly correlates with relative warmth-to-weight ratio, and allows for comparison of different sleeping bag chassis with different fill weights of different fill powers. From an ultralight backpacking perspective, this is the most important statistic, and the one we value highest.
Best Overall Lightweight 0 Degree Sleeping Bag
Sea to Summit Spark 0
The newly released 2024 edition of Sea to Summit Spark 0 immediately jumped to the top of our zero degree sleeping bag guide due to its exceptional warmth-to-weight ratio, superior to all other 0 degree quilts we’ve covered. This is due to the combination of lightweight shell fabric (10d nylon) and copious amounts of 850 fill power down. The total weight of this sleeping bag is 75% down weight, 25% shell weight, which is an exceptionally high ratio. Features wise, this sleeping bag is quite minimalist, which is part of what makes it so effective. We’re grateful for the transitional baffles which change from horizontal to vertical at the torso in order to prevent gravity induced down-drift. The zipper slider plow is extremely effective, and the head hole can be cinched down tight. All said and done, Sea to Summit Spark 0 has the best stats of any 0 degree sleeping bag we’ve ever covered.
- Price: $649
- Total Weight: 39.3 oz
- Fill Weight: 29.6 oz
- Fill Power: 850 in³/oz
- Down Volume: 25,160 in³
- Down Volume/Total Weight: 640 in³/oz
- Shell Fabric: 10d
- Shoulder/Hip Circumference: 61″/53″
- Pros: Highest warmth-to-weight ratio. Great relative value. Ultralight shell material and good quality down.
- Cons: Expensive.
Compared to the average 0 degree sleeping bag in this guide, Sea to Summit Spark 0 is as-expensive, warmer, lighter weight, average width, and has a much higher warmth-to-weight ratio.
Next Best Lightweight 0 Degree Sleeping Bag
Western Mountaineering Kodiak MF 0
We’ve been down on Western Mountaineering’s summer bags for being over-costed relative to their good-not-great warmth-to-weight ratios. But winter is a different story! With 30 oz of 850 fill power down, and enough extra room to comfortably wear a puffy jacket to bed, Kodiak MF is statistically superior in nearly all regards to all but one other bag on this list, and our list is already filtering out average and below-average quality models. The wide fit, especially at the shoulders, is notable and will likely help users sleep more comfortably, and accommodate wearing a puffy to bed in extreme cold, even if it dilutes the concentration of down somewhat. For $835, this 0 degree sleeping bag is an absolute wallet bruiser. But the quality is there if you want it!
- Price: $835
- Total Weight: 44 oz
- Fill Weight: 30 oz
- Fill Power: 850 in³/oz
- Down Volume: 25,500 in³
- Down Volume/Total Weight: 580 in³/oz
- Shell Fabric: 20d
- Shoulder/Hip Circumference: 66″/57″
- Pros: Statistically better than average by every measurement. Comfortable wide fit.
- Cons: Very expensive within an already expensive category. Wide fit dilutes concentration of down insulation.
Compared to the average 0 degree sleeping bag in this guide, Western Mountaineering Kodiak MF 0 is more expensive, warmer, lighter weight, wider, and has a higher warmth-to-weight ratio.
Highest Warmth-to-Weight 0 Degree Sleeping Bag
Mountain Hardwear Phantom 0
We’ll admit we were as shocked as you are to learn that Mountain Hardwear, a brand that has been trending less technical over the years, manufactures a 0 degree sleeping bag with one of the very highest warmth-to-weight ratios on the market. But all it takes to win that contest is stuffing copious amounts of high fill power down into an ultralight shell, and the Phantom 0 certainly hits the mark. The biggest downside, apart from the more-expensive-than-average price tag, is how narrow this 0 degree sleeping bag is. It’s not good for wide shoulders, wide hips, or large bodies in general, and this is what’s holding it back from the top spot. Phantom puts the mummy in mummy bag! But the upside to narrowness is that it reduces weight and concentrates the heat around you, making it even more effective for those who can fit it.
Notably, this bag was updated for 2024, now uses recycled shell fabrics (same as in Ghost Whisperer Jackets), and has been downgraded from 850 fill power to 800. Otherwise, it’s the exact same design.
- Price: $680
- Total Weight: 42.6 oz
- Fill Weight: 30 oz
- Fill Power: 850 in³/oz
- Down Volume: 25,500 in³
- Down Volume/Total Weight: 599 in³/oz
- Shell Fabric: 10d/15d
- Shoulder/Hip Circumference: 58″/52″
- Pros: Highest warmth-to-weight ratio. Ultralight shell fabric.
- Cons: Quite narrow.
Compared to the average 0 degree sleeping bag in this guide, Mountain Hardwear Phantom 0 is more expensive, warmer, lighter weight, narrower, and has a higher warmth-to-weight ratio.
Best Value & Best Ultralight 0 Degree Sleeping Bag
Outdoor Vitals Summit Down 0
The value proposition for Outdoor Vitals Summit Down 0 Degree Sleeping Bag is preposterously favorable. It has the second highest warmth-to-weight ratio in our guide for the second lowest price. And it’s hand down the lightest weight, and an easy pick for best ultralight 0 degree sleeping bag. The only downside is that it’s slightly underfilled in terms of down quantity, thus a bit less warm than average. If we’re being honest, we think calling it the Summit Down 5 would have been more earnest. But that doesn’t make it any less exceptional as a piece of ultralight gear. What a buy!
- Price: $430
- Total Weight: 35 oz
- Fill Weight: 25.8 oz
- Fill Power: 800 in³/oz
- Down Volume: 20,640 in³
- Down Volume/Total Weight: 590 in³/oz
- Shell Fabric: 10d
- Shoulder/Hip Circumference: 60″/54″
- Pros: Lightest in category. Very affordable. Ultralight shell fabric.
- Cons: Slightly underfilled, less warm than average.
Compared to the average 0 degree sleeping bag in this guide, Outdoor Vitals Summit Down 0 is much less expensive, less warm, much lighter weight, as wide, and has a higher warmth-to-weight ratio.
Best Budget Winter Sleeping Bag
Mountain Hardwear Bishop Pass 0
Look, winter gear is expensive enough already, which is what makes the Mountain Hardwear Bishop Pass such a tempting choice for your 0 degree sleeping bag. At $325, it’s nearly half as expensive as the average model on this list! And while yes, it’s heavier, bulkier, and slightly less warm than average, for the most part, it keeps pace with the rest of the group. Arguably a bigger issue than its middling stats though, is its narrowness at the hips. While it’s shoulder girth is average, this tapers down to become the narrowest bag on our list, making it incompatible for some body types. Double check your measurements before purchasing, but if it fits you, what a killer value!
- Price: $325
- Total Weight: 50 oz
- Fill Weight: 33 oz
- Fill Power: 650 in³/oz
- Down Volume: 21,450 in³
- Down Volume/Total Weight: 429 in³/oz
- Shell Fabric: 20d
- Shoulder/Hip Circumference: M’s: 62/53″ W’s: 60″/50″
- Pros: Very affordable.
- Cons: Narrow at the hips. Heavy. Low quality down fill. Bulky.
Compared to the average 0 degree sleeping bag in this guide, Mountain Hardwear Bishop Pass 0 is more much less expensive, slightly less warm, heavier, narrower at the hips, and has a lower warmth-to-weight ratio.
Best Wide 0 Degree Sleeping Bag
The North Face Inferno 0
The best thing going for the North Face Inferno 0 is that it is wide and non-constrictive. But aside from its best-in-class girth, this sleeping bag is completely average among the other top tier bags across nearly every statistic. While its shoulder/hip width increases comfort, the downside is that it dilutes the concentration of down plumes by spreading them out thinner across more baffles. But if you must have a wide bag, this is a great one to go for!
- Price: $590
- Total Weight: 42 oz
- Fill Weight: 29 oz
- Fill Power: 800 in³/oz
- Down Volume: 23,200 in³
- Down Volume/Total Weight: 552 in³/oz
- Shell Fabric: 15d
- Shoulder/Hip Measurement: 64″/60″
- Pros: Wide and comfy.
- Cons: Average stats across the board.
Compared to the average 0 degree sleeping bag in this guide, The North Face Inferno 0 is as expensive, as warm, as heavy, wider, and has an average warmth-to-weight ratio.
Top Pick Lightweight 0 Degree Sleeping Bag
Therm-a-Rest Parsec 0
We measured and compared stats for two dozen 0 degree sleeping bags, and Therm-a-Rest Parsec was a solid contender with above average stats. However it’s just on the outside of the top tier looking in. It stands out for a nice blend of low weight and high performance. That said, it’s not the lightest, nor is it the warmest, nor is it the best value. It’s just not the best at anything, and what’s more, it’s a bit underfilled. That means less warmth than the top-tier-bag average, and it would probably be more accurate to replace the zero in its name with a five. Bottom line, the Parsec is great-not-excellent, and a great value opportunity if you can find it on sale.
- Price: $570
- Total Weight: 38 oz
- Fill Weight: 26 oz
- Fill Power: 800 in³/oz
- Down Volume: 20,800 in³
- Down Volume/Total Weight: 547 in³/oz
- Shell Fabric: 20d
- Shoulder/Hip Circumference: 63″/58″
- Pros: Lightweight. A bit wider than average.
- Cons: Slightly underfilled, less warm than average
Compared to the average 0 degree sleeping bag in this guide, Therm-a-Rest Parsec 0 is slightly less expensive, less warm, lighter weight, wider, and has a higher warmth-to-weight ratio.
Best Waterproof 0 Degree Sleeping Bag
Feathered Friends Snowbunting, Murre, Ibis ES 0
Feathered Friends is a top purveyor of expedition grade sleeping bags, and their Snowbunting (M’s), Murre (W’s), and Ibis (Wide) ES series, all different shapes of the same overall model, are notable for their use of waterproof/breathable outer shell fabrics. This can be important if your sleeping bag will be exposed to cold/damp air, wind, snow, etc, or in damp frozen climates where heavy coatings of wet frosts are likely to form on your sleeping bag overnight. They’re great for snow camping, such as a dug out shelter underneath a pyramid tent.feat The downside being, they’re heavier and a bit clammier on the inside and don’t breath as well, so you don’t want waterproof unless you need it. Beyond that, each model is an exemplary 0 degree sleeping bag with high quality down and exceptional craftsmanship.
Below stats reflect Snowbunting ES 0. The Murre and Ibis will be similar.
- Price: $789
- Total Weight: 45.3
- Fill Weight: 25.3 oz
- Fill Power: 900 in³/oz
- Down Volume: 23,940 in³
- Down Volume/Total Weight: 528 in³/oz
- Shell Fabric: 15d/40d Pertex Shield Air
- Shoulder/Hip Circumference: M’s 60″/56″
- Pros: Waterproof shell fabric. M’s, W’s, and Wide versions. High quality fill power. Exceptional craftsmanship. Made in USA
- Cons: Expensive. Waterproof shell adds weight, is less breathable than non-waterproof.
Compared to the average 0 degree sleeping bag in this guide, Feathered Friends Snowbunting, Murre, and Ibis are more expensive, as warm, as heavy, as wide and have an average warmth-to-weight ratio.
In Conclusion
Thanks for reading about what we believe are the best 0 degree sleeping bags for winter backpacking. Every model has a good warmth-to-weight ratio, and should be comfortable in the 10-25F range, adjusting for your personal heat output. We hope you found the winter sleeping bag of your dreams! Drop us a line in the comments if you have any questions.
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