Best 0 Degree Sleeping Bags: 9 Picks Compared

Our verdict

Our Top Picks

A “0 degree” sleeping bag is not one kind of bag. On some bags 0°F is the ISO or EN limit rating, the lab figure for a curled-up sleeper, and the same bag carries a comfort rating around 14°F. On others 0°F is the maker’s own figure with no standard behind it, and TETON’s 0°F is a survival rating that TETON itself says to read as comfortable at about 25°F to 30°F. So this guide gives every bag’s rating by its type and does not line up ratings of different types against each other.

We compared nine 0°F bags that Amazon stocks, from ultralight 850- and 900-fill down mummies for backpacking to synthetic bags for car camping and larger sleepers. Every figure comes from the maker’s own page or, where the maker’s site refused us, the maker’s Amazon listing, and each review says which.

Compare the picks

Compare the 9 Sleeping Bags

Every row is the exact size we link. The rating cell names its type: “ISO” and “EN” figures come from the standard lab test the maker names; “own rating” means the maker names no standard; TETON’s figure is its survival rating. Ratings of different types are not comparable, so read each one only against its own type. Weights are the maker’s figure for the linked size.

How We Chose These 0°F Bags

What we required of a 0°F pick

• The maker rates the bag at or near 0°F on its own label: 0°F as an ISO or EN limit, 0°F as its own rating, or 0°F as a survival rating. Big Agnes rates the Lost Ranger 3N1 0° at an ISO limit of -1°F with both bags together.
• The rating type is stated, or the maker’s note on how it rates is on its own page, so we can label it.
• Amazon showed the exact size and zip side we link, new and in stock, when we checked on 2026-10-22.
• Several brands, from entry-level synthetic bags to premium down, with no two picks doing the same job.
• Bags whose maker page we could not read and whose Amazon listing gives no rating or weight were left out: that removed the Mountain Hardwear Phantom 0 and Lamina 0, which ranking guides cover.

Where the figures come from and what owners on Reddit say about 0°F bags

Where the figures come from

Ratings, fill, weights and packed sizes come from the makers’ pages: Sea to Summit, Therm-a-Rest, NEMO, Western Mountaineering, Big Agnes, Klymit and TETON. Coleman’s site refused our requests, so the Coleman North Rim’s figures come from the maker’s Amazon listing, which Amazon.com sells. Where a maker’s page and Amazon’s listing give different figures, the review says so and we use the maker’s.

Independent tests cover three picks. OutdoorGearLab’s winter sleeping bag review tested the Kodiak MF in the 6’0″ size we link and the NEMO Sonic in its -20°F version. The Adventure Gene and Backwoods Pursuit used the Spark 0°F (Backwoods Pursuit in the Regular; The Adventure Gene does not name the length it camped in, and its spec table lists the Regular); we link the Long. The other picks rest on maker specs or owner reports, and their evidence lines say so.

What owners on Reddit say about 0°F bags

In the r/CampingandHiking “0 degree bag recommendations?” thread, Western Mountaineering came up more than any other brand. One reply read, “I’d vote for eating ramen for a few weeks and snagging a WM Antelope or Kodiak.” Another owner wrote, “I personally like Thermarest sleeping bags because they are typically way more accurate with the rating than other companies,” about an older Therm-a-Rest 0°F bag they said the Parsec has replaced. A third reply made the rating point directly: “Women’s bags are usually listed according to the comfort limit and men’s bags are listed according to the lower limit.” These are owner opinions, not tests.

Detailed Reviews

Sea to Summit Spark 0°F, 850-Fill Down Mummy

The Spark 0°F is the 0°F version of Sea to Summit’s ultralight down bag, which also comes in 15°F, 30°F and 45°F versions. Sea to Summit gives it an ISO limit (“ISO Lower”) of 0°F (-18°C) and an ISO comfort rating of 14°F (-10°C). The Long we link holds 33.33 oz of RDS-certified 850+ fill goose down with Sea to Summit’s Ultra-Dry Down treatment, inside a 10D nylon shell and liner, and weighs 42.5 oz (1204 g) by the maker’s figure. It fits sleepers up to 198 cm (about 6 ft 6 in); the Regular, rated the same, fits up to 185 cm. The Regular was not in stock on Amazon when we checked, which is why we link the Long.

The Adventure Gene, an Australian guided-trip company that owns more than 10 Spark -18°C bags for its guided snow-camping trips, spent about 30 nights snow camping in them, with a coldest night of -15°C, and wrote, in a comparison of bags for Australian alpine conditions, “However, the Sea to Summit Spark -18°C (-0°F) stands as a worthy competitor and is arguably the best winter sleeping bag on the market.” Backwoods Pursuit used the Regular on late-season hunts from a bag Sea to Summit supplied and wrote, “The temperature ratings (0° F lower limit, 14° F comfort limit) felt accurate to me.” Backwoods Pursuit tested the Regular, and The Adventure Gene’s spec table lists the Regular; neither covers the Long.

Related guide: Best Cold Weather Sleeping Bags for Backpacking: 8 Picks Compared

Related guide: Best Cold Weather Sleeping Pads: 9 Picks Compared

Evidence: Independently reviewed, same series. The Adventure Gene: Spark -18°C (0°F), Regular.

Specs: Sea to Summit Spark 0°F, Long

• Rating: ISO limit 0°F (-18°C); ISO comfort 14°F (-10°C)
• Fill: 850+ fill power goose down, RDS, Ultra-Dry Down; 33.33 oz (945 g) in the Long
• Weight: 42.5 oz (1204 g), Long; packed weight with sacks 45.8 oz (1299 g)
• Packed size: 18 x 11 x 7 in (46 x 27.5 x 18 cm); compressed volume 10.6 L
• Shape: contoured mummy
• Lengths: Regular (fits to 185 cm), Long (fits to 198 cm)
• Shell and liner: 10D nylon, non-PFAS DWR
• Price tier: $$$

Therm-a-Rest Parsec 0F, 900-Fill Down Bag

The current Parsec 0F uses 900-fill hydrophobic duck down, RDS-certified and PFAS-free, in a 20D recycled nylon ripstop shell. Therm-a-Rest labels its ratings “EN” and gives an EN limit of 0°F (-18°C) and an EN comfort rating of 14°F (-10°C). The Regular we link holds 27 oz of down, weighs 2 lb 7 oz (1100 g) and packs to 7.5 x 11 in, all by Therm-a-Rest’s spec table. It fits sleepers up to 72 in, with a girth of 62 in at the shoulder, 57 in at the hip and 42 in at the footbox. Features include zoned insulation, a “Toe-asis” foot warmer pocket in the footbox, an internal stash pocket and loops for adding a quilt.

Amazon’s page title for this listing ends in “Long”, but its own variant selector marks it as the standard size, its model number 14384 is Therm-a-Rest’s Regular SKU, and its price matches the Regular. We found no independent test of this 900-fill version yet. One owner on Reddit, quoted above, rates Therm-a-Rest’s 0°F labels as accurate; that comment was about an older bag.

Evidence: No independent test; maker specs. Source: Therm-a-Rest product page.

Specs: Therm-a-Rest Parsec 0F, Regular (SKU 14384)

• Rating: EN limit 0°F (-18°C); EN comfort 14°F (-10°C)
• Fill: 900-fill PFAS-free hydrophobic duck down, RDS; 27 oz (762 g)
• Weight: 2 lb 7 oz (1100 g), Regular
• Packed size: 7.5 x 11 in (19 x 30 cm)
• Fit: up to 72 in; girth 62 / 57 / 42 in (shoulder / hip / footbox)
• Lengths: Regular, Long
• Shell: 100% recycled 20D nylon ripstop, DWR
• Price tier: $$$

NEMO Sonic 0°F, Vented Down Mummy

NEMO’s Sonic comes in -20°F and 0°F versions; we link the 0°F Regular. NEMO gives it an ISO limit of 0°F (-18°C) and an ISO comfort rating of 14°F (-10°C). It holds 1 lb 12 oz (790 g) of 800 FP hydrophobic down and has a minimum weight of 3 lb 4 oz. Its distinguishing feature is a pair of zippered Thermo Gill vents on top; NEMO writes, “Integrated Thermo Gill™ vents extend the comfort range and create fine-tuned control with their multistage zipper system.” It also has a waterproof-breathable “Toester” footbox and stretch panels at the knees.

OutdoorGearLab tested the Sonic -20, the colder sibling with more down, not this 0°F version. OGL wrote, “Testers also slept comfortably in temperatures as high as 40°F with the innovative upper vents unzipped and the main zipper slightly opened (though we don’t recommend this if you sleep warm).” On fit it wrote, “Though marketed for people up to 6 feet tall, our 6-foot tester found his feet pressed too tightly against the end, compromising insulation.” The 0°F Regular we link has the same 6 ft listed fit.

Evidence: Independently reviewed, same series. OutdoorGearLab: Sonic -20°F, regular.

Specs: NEMO Sonic 0°F, Regular

• Rating: ISO limit 0°F (-18°C); ISO comfort 14°F (-10°C)
• Fill: 800 FP hydrophobic down, RDS; 1 lb 12 oz (790 g)
• Weight: 3 lb 4 oz minimum; 3 lb 6 oz packed (Regular)
• Packed size: 13.5 x 9.5 in diameter; compressed volume 9.6 L
• Fit: up to 6 ft; girth 63 / 58 / 53 in (shoulder / hip / knee)
• Lengths (0°F): Short, Regular, Long
• Price tier: $$$

Western Mountaineering Kodiak MF, Wide-Cut Down Bag

Western Mountaineering describes the Kodiak MF as a wide cold-weather bag for side sleepers, larger users and anyone who does not want to feel confined. The 6’0″ size we link holds 30 oz of 850+ fill goose down, weighs 2 lb 12 oz by the maker’s table and has an inside girth of 66 in at the shoulder, 57 in at the hip and 41 in at the foot. Its 0°F rating is WM’s own. WM’s ratings page says, “All Western Mountaineering bags have a temperature rating based on extensive field use and carefully calculated fill weights,” and adds, “We also have EN/ISO testing data available for most of our models, and you’ll find that the WM rating usually falls somewhere between the ‘limit’ and ‘comfort’ ratings derived from that protocol.” WM prints no EN or ISO figure on the Kodiak’s page. The page’s prose gives 2 lb 15 oz, which matches its 6’6″ row; we use the 6’0″ figure. It is made in the USA.

OutdoorGearLab named it Best Overall Winter Sleeping Bag after testing the 6’0″ size; one tester said, “I found it incredibly comfortable — like it’s radiating heat.” OGL also wrote, “We’ve found that Western Mountaineering tends to be conservative in its ratings, and we’ve used this bag in temps as low as -10°F with a light fleece blanket for extra insulation.” On Amazon this listing is sold and shipped by Outland USA, a third-party seller, below WM’s own list price when we checked.

Evidence: Independently reviewed, exact model. OutdoorGearLab: Kodiak MF, 6’0″ (regular).

Specs: Western Mountaineering Kodiak MF, 6’0″, right zip

• Rating: 0°F (-18°C), Western Mountaineering’s own field-based rating; no EN/ISO figure published on the product page
• Fill: 850+ fill power goose down; 30 oz (6’0″)
• Weight: 2 lb 12 oz (6’0″)
• Packed size: 9 x 18 in stuff size
• Fit: inside girth 66 / 57 / 41 in (shoulder / hip / foot), 6’0″
• Lengths: 6’0″, 6’6″, 7’0″; left or right zip
• Shell: 20D MicroLite XP
• Price tier: $$$

Big Agnes Lost Ranger 3N1 0°, Modular 3-in-1 System

The Lost Ranger 3N1 is two bags: an outer bag and an inner bag that zip together. Big Agnes publishes ISO figures for each setup: with both bags, ISO comfort 12°F and ISO limit -1°F; with the inner bag alone, ISO comfort 29°F and ISO limit 18°F. It uses 650 fill DownTek, PFC-free down with a water-repellent treatment, 27 oz in all (18 oz inner, 9 oz outer). Big Agnes lists the total weight at 3 lb 5 oz (inner bag 1 lb 14 oz, outer bag 1 lb 7 oz); Amazon’s listing says 3.8 pounds, and we use the maker’s figure. The outer bag has a Padlok sleeve that holds a sleeping pad so you do not roll off it, and it can be used alone on warm nights.

We found no independent test of the 0° version. On Amazon the buy box moved between two outdoor sellers, Backcountry and Ridgeline Insights, while we checked; both were at Big Agnes’s list price.

Evidence: No independent test; maker specs. Source: Big Agnes product page.

Specs: Big Agnes Lost Ranger 3N1 0°, Regular

• Rating: both bags ISO comfort 12°F, ISO limit -1°F; inner bag alone ISO comfort 29°F, ISO limit 18°F
• Fill: 650 fill DownTek; 27 oz total (18 oz inner, 9 oz outer)
• Weight: 3 lb 5 oz total (Big Agnes; Amazon lists 3.8 lb)
• Packed size: 9.5 x 13.5 in compressed; stuff sack 9 x 20 in
• Fit: girth 59 / 51 / 40 in inner, 66 / 58 / 52 in outer (shoulder / hip / foot)
• Sizes: Small, Regular, Long
• Price tier: $$

Klymit Sojourn Stretch 0, Stretch Synthetic, Large

Klymit’s 0°F bag is the Sojourn Stretch 0, a synthetic bag with what Klymit calls Flexible Stretch Baffles, which stretch as you move, and Length Locks, which shorten the bag to your height. Klymit rates it “0°F (-18°C)” and names no test standard. The Large we link measures 82 x 40 in, weighs 5.5 lb and packs to 17 x 11 in, by Klymit’s figures, with a 20D nylon water-resistant shell, a mummy hood with draft collar and a two-way YKK zipper.

Klymit’s site listed only the Large, sold out, when we checked; Amazon sells it new, sold by Amazon.com. We found no independent test or owner report specific to this bag.

Evidence: No independent test; maker specs. Source: Klymit product page.

Specs: Klymit Sojourn Stretch 0, Large

• Rating: 0°F (-18°C), Klymit’s own rating; no standard named
• Fill: synthetic
• Weight: 5.5 lb (2.5 kg), Large
• Packed size: 17 x 11 in (43 x 28 cm)
• Size: 82 x 40 in (208 x 102 cm); a Regular also sells on Amazon
• Shell: 20D nylon, water-resistant
• Price tier: $$

TETON LEEF 0°F, Budget Synthetic Mummy

TETON’s LEEF is a synthetic mummy sold in 0°F, 20°F and 30°F versions; we link the 0°F Regular in Black/Sage. TETON’s 0°F is a survival rating. TETON’s page says, “The ratings we use are Survival Temperature Ratings, this is the coldest temperature the sleeping bag is designed to keep you alive in, but it doesn’t guarantee comfort.” TETON lists the 0°F LEEF’s comfort range as 25°F to 30°F. The Regular measures 81 x 30 in at the shoulders, tapering to 21 in at the foot, weighs 4.2 lb and packs to 16.25 x 10.5 x 10 in in its compression sack, all by TETON’s figures. It uses TETON’s PolarLite Micro insulation, a brushed polyester liner and a 3/4-length left zip.

We found no independent test. In an r/CampingandHiking thread from a LEEF owner asking about its range, one reply read, “Be careful with Teton bags – Teton is a bit of an outlier in that they rate their bags on ‘extreme’ or ‘survival’ ratings, while just about everyone else uses ‘limit’ ratings.” That matches TETON’s own note.

Evidence: No independent test; maker specs. Source: TETON product page.

Specs: TETON LEEF 0°F, Regular, Black/Sage

• Rating: 0°F, TETON survival rating; comfort 25°F to 30°F per TETON
• Fill: PolarLite Micro synthetic insulation
• Weight: 4.2 lb (Regular 0°F)
• Packed size: 16.25 x 10.5 x 10 in (Black/Sage Regular)
• Size: 81 x 30 in at the shoulders, 21 in at the foot
• Lengths: Short, Regular, Long
• Price tier: $

Coleman North Rim 0°F, Big & Tall Synthetic

Coleman’s North Rim is a synthetic mummy sized for “campers up to 6 ft. 2 in” at 82 x 32 in. Coleman’s site refused our requests, so every figure here is from the maker’s Amazon listing, which Amazon.com sells. The listing says “Stay warm in temperatures as low as 0°F” and names no test standard, so we read 0°F as Coleman’s own rating. It uses Coletherm hollow polyester insulation, a Thermolock draft tube along the zipper, an adjustable hood and a no-snag zipper, and it is machine washable with a 5-year limited warranty. The listing gives no weight and no packed size.

We found no independent test or owner report specific to the 0°F North Rim.

Evidence: No independent test; maker specs. Source: Coleman’s Amazon listing.

Specs: Coleman North Rim 0°F (maker’s Amazon listing)

• Rating: 0°F, Coleman’s own rating (“as low as 0°F”); no standard named
• Fill: Coletherm hollow polyester
• Weight: not published
• Packed size: not published
• Size: 82 x 32 in; fits campers up to 6 ft 2 in
• Warranty: 5-year limited
• Price tier: $

TETON Celsius 0°F, Rectangular Camp Bag

The Celsius is TETON’s oversized rectangular bag with a mummy-style hood, sold in -25°F, 0°F and 20°F versions; we link the 0°F Regular in green with a left zip. Like the LEEF, its 0°F is a TETON survival rating, and TETON lists its comfort range as 25°F to 30°F. It measures 80 x 33 in, uses SuperLoft Elite hollow fiber fill with a flannel liner and packs to 16.75 x 11.25 x 11.25 in, with a pack weight of 6.66 lb, by TETON’s page. TETON’s page for this version leaves the bag’s own weight blank; Amazon’s listing gives 5 lb.

An owner on r/CampingGear wrote, “I have this sleeping bag. My coldest night in it has been high 20’s in a tent,” and, after waking chilly in shorts and a shirt, “I run kinda hot, but I’d say this bag when you dress correctly is good for low 20’s or maybe a bit colder.” That is one owner’s experience.

Evidence: No independent test; owner reports. r/CampingGear owner thread: Celsius 0°F, size not stated.

Specs: TETON Celsius 0°F, Regular, green, left zip

• Rating: 0°F, TETON survival rating; comfort 25°F to 30°F per TETON
• Fill: SuperLoft Elite single-channel hollow fiber
• Weight: not published for this version (Amazon lists 5 lb); pack weight 6.66 lb
• Packed size: 16.75 x 11.25 x 11.25 in
• Size: 80 x 33 in
• Shape: rectangular with a mummy-style hood
• Price tier: $

Buying Guide: Reading a “0 Degree” Label

Comfort, limit, own rating and survival rating

The ISO 23537 test, which replaced EN 13537, gives two main figures: a comfort rating, the temperature a standard sleeper is comfortable at in a relaxed position, and a limit rating, for a standard sleeper curled up. Sea to Summit, NEMO and Big Agnes publish both as ISO; Therm-a-Rest labels its pair EN. On those bags “0°F” is the limit, and the comfort figure is the one to plan around: 14°F on the Spark, Parsec and Sonic, and 12°F on the Lost Ranger 3N1 with both bags. Western Mountaineering, Klymit and Coleman give their own 0°F ratings without a standard; WM says its rating usually falls between the ISO limit and comfort figures. TETON’s 0°F is a survival rating, and TETON lists the comfort range as 25°F to 30°F. OutdoorGearLab puts the problem this way: “Many companies advertise the lower limit for safe use, NOT the lower limit for comfort.” Compare bags only within one rating type.

Down or synthetic

The premium picks use goose or duck down at 650 to 900 fill power, and several makers treat the down to resist moisture: Sea to Summit’s Ultra-Dry Down, Therm-a-Rest’s and NEMO’s hydrophobic down, Big Agnes’s DownTek. The Klymit, TETON and Coleman bags use synthetic fill, which these makers sell as warm in damp conditions and which costs less, at the price of weight and bulk. Adventure Alan’s 0 degree guide compares down bags by down volume (fill weight times fill power) rather than by their ratings, and says of down volume, “It strongly correlates with the insulative ability of a sleeping bag.”

Weight and packed size for backpacking

If you are backpacking, read the weight for the size you will buy, since the Long and the 6’6″ sizes weigh more. On the makers’ figures, the Spark Long is 42.5 oz, the Parsec Regular 2 lb 7 oz, the Kodiak MF 6’0″ 2 lb 12 oz and the Sonic Regular 3 lb 4 oz minimum. “Ultralight” on a label is the maker’s word; check the number.

Fit, length and layers

A 0°F bag is often used with a down jacket inside, so girth matters. The Kodiak MF’s 66 in shoulder girth and the Klymit Large’s wide cut leave more room than a close mummy; OutdoorGearLab’s 6 ft tester found the Sonic -20 regular short. Pick the length that fits you with a little room at the feet, not the shortest one.

The pad under the bag

A bag’s rating assumes an insulated pad under it, and a 0°F bag on a thin pad is likely to feel colder than its rating suggests. Western Mountaineering says its ratings assume “A properly insulated ground pad (around R 5.0+ for colder conditions)”, “A set of dry base layers” and “A pair of socks”. Our sleeping pad guide explains R-values, and the winter tent guide and how to insulate a tent for winter cover the shelter around the bag. If you camp with a heated tent, see our tent stove guide.

Frequently Asked Questions

It depends on the rating type. On the ISO- and EN-rated bags here, 0°F is the limit and the comfort rating is 14°F (12°F for the Lost Ranger 3N1 with both bags). TETON’s 0°F is a survival rating, with comfort at 25°F to 30°F by TETON’s own figures. Adventure Alan’s guide, about the down bags it covers, says, “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.”

Go by the coldest nights you expect and the comfort figure, not the headline number. OutdoorGearLab writes, “A common rule of thumb is to buy a bag that’s rated about 20 degrees lower than the temperatures you will regularly experience.” Adventure Alan writes that for nights well below freezing, “Three-season models rated 20-30F are not sufficient.”

0°C is 32°F. Look at the comfort figure for its type: ISO or EN comfort 14°F for the Spark, Parsec and Sonic, ISO comfort 12°F for the Lost Ranger 3N1 with both bags, and TETON’s comfort range of 25°F to 30°F for the LEEF and Celsius. Western Mountaineering, Klymit and Coleman publish no comfort figure for their bags here. Bring a pad suited to the cold and sleep clothes either way.

We do not rank weights across makers’ different sizes and methods. By the makers’ own figures for the sizes we link, the Spark Long weighs 42.5 oz, the Parsec Regular 2 lb 7 oz and the Kodiak MF 6’0″ 2 lb 12 oz. Adventure Alan, within the seven bags its guide covers, writes of the Outdoor Vitals Summit Down 0, “And it’s hand down the lightest weight, and an easy pick for best ultralight 0 degree sleeping bag.” We did not find that bag on Amazon, so it is not a pick.

Yes, the Sojourn Stretch 0, a synthetic bag Klymit rates at 0°F (-18°C) without naming a standard. It is review 6 above.

For carrying, check each bag’s weight at the size you will buy in its review; the 0°F labels here are different rating types, so weight alone does not compare warmth like for like. For car camping, where weight matters less, the synthetic bags sit in the $ and $$ price tiers.

The bottom line

Final Verdict

For a light down bag to carry, the Sea to Summit Spark 0°F (check price) has an ISO limit of 0°F and an ISO comfort rating of 14°F at 42.5 oz for the Long. For room to sleep on your side, the Western Mountaineering Kodiak MF (check price) is a wide-cut 850-fill bag that OutdoorGearLab tested in the size we link; its 0°F is WM’s own field-based rating. For low-cost car camping, the TETON Celsius 0°F (check price) is a roomy flannel-lined bag, and TETON’s own comfort range of 25°F to 30°F is the figure to plan around. The other six picks cover 900-fill down, vented down, a modular 3-in-1 system, a stretch synthetic bag, a budget synthetic mummy and a big-and-tall mummy, and each review names its rating type and source.

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.