Best Backpacking Sleeping Bags: 5 Picks and How to Read Temperature Ratings

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Last updated: November 2026

For three-season backpacking, look for a bag with an ISO lower limit around -7 to -4°C (20 to 25°F) that weighs under 1.5 kg (3.3 lb). The five bags below cost from $39.99 to $259.95 on Amazon (price on November 1, 2026). Temperature ratings differ in how they were measured, so the table notes which ones are ISO tested.

Prices are from Amazon.com on November 1, 2026 and change often. Specs are from each manufacturer unless noted.

1. Kelty Cosmic 20 Down: lightest bag here

The Cosmic 20 is a mummy bag with 550-fill down and ISO-tested ratings. It’s the lightest and most packable bag on this list.

Key specs (manufacturer):

• Weight: 1.19 kg (2 lb 10 oz), Regular (fits up to 6 ft)
• Fill: 550 fill power down, about 464 g (16.4 oz)
• ISO comfort 32°F (0°C); ISO limit 21°F (-6°C)
• Recycled fabrics with PFAS-free DWR

Pros

• ISO ratings make it easy to compare
• Packs much smaller than the synthetic bags
• Good warmth for the weight at this price

Downsides

• 550 fill is heavier and bulkier than premium 800 to 850 fill down
• Down loses warmth when wet, so pack it in a dry bag
• Low stock: only 6 left of the Regular on Amazon when checked (the Short had 14)

Check the Kelty Cosmic 20 Down price on Amazon

2. NEMO Forte 20 Endless Promise: roomy synthetic for side sleepers

The Forte uses NEMO’s spoon shape, wider at the elbows and knees, which suits side sleepers. It’s synthetic, so it keeps more warmth when damp than down.

Key specs (manufacturer):

• Minimum weight: 1.5 kg (3 lb 5 oz); packed 1.59 kg (3 lb 8 oz), Regular
• ISO comfort 29°F (-2°C); ISO limit 18°F (-8°C)
• Packed size: 18 x 9.5 in (46 x 24 cm)
• Synthetic insulation; Endless Promise line is designed to be recyclable

Pros

• Warmest ISO limit on this list
• Spoon shape gives room to move
• Handles damp better than down

Downsides

• About 300 g (0.7 lb) heavier than the Kelty and packs larger
• Regular size had only 3 left on Amazon when checked; the Long Wide is $259.95
• Pricier than other synthetic bags

Check the NEMO Forte 20 price on Amazon

3. TETON Sports Altos-S 0°F: cheap warmth, read the rating carefully

The Altos-S is a synthetic mummy bag sold as a 0°F bag. TETON lists its comfort rating as 30°F (-1°C). The 0°F figure is the survival rating, not a comfortable night.

Key specs (manufacturer):

• Weight: 1.6 kg (3.5 lb)
• Synthetic microfiber fill; 20D polyester ripstop shell
• Comfort 30°F (-1°C); extreme 0°F (-18°C); not ISO tested
• Size 84 x 32 x 17 in; packed 14 x 8 x 8 in

Pros

• Low price for a mummy bag with a full hood
• Synthetic fill copes with damp
• Compression sack included

Downsides

• The 0°F name oversells it: plan around the 30°F comfort figure
• Heavier and bulkier than the down bag
• Ratings are not ISO tested, so they’re hard to compare with Kelty or NEMO

Check the TETON Altos-S price on Amazon

4. RIOYALO 0 Degree Sleeping Bag: roomy budget bag for tall campers

The RIOYALO is a large envelope-shaped bag with a hood. It’s sold as a 0 degree bag, but the maker’s own comfort rating is 32°F (0°C), so treat it as a three-season car-camping bag.

Key specs (manufacturer):

• Weight: 2.3 kg (5 lb)
• Size: 86.6 x 30.7 in (7.2 x 2.6 ft)
• Comfort 32°F (0°C); limit 15°F (-9°C); extreme 5°F (-15°C); not ISO tested
• 450 gsm polyester fill; 210T ripstop shell; packed 15.6 x 7.6 in

Pros

• Long and wide for tall sleepers
• Machine washable
• Compression sack included

Downsides

• The 0 degree name is misleading: the comfort rating is 32°F
• Heavy and bulky for carrying on a trek
• Many owner reviews mention zipper and seam problems; 15 left when checked

Check the RIOYALO sleeping bag price on Amazon

5. KANYAK 32°F Sleeping Bag: summer and budget only

The KANYAK is a semi-rectangular polyester bag for warm nights, sleepovers and car camping. It’s on this list as the cheapest option, not as a cold-weather backpacking bag.

Key specs (manufacturer):

• Weight: about 1.8 kg (4 lb)
• Size: 86.6 x 32.5 in; packs to about 11 to 14 in long
• Comfort 41°F (5°C); limit 32°F (0°C); not ISO tested
• 210T polyester shell with water-resistant finish; machine washable

Pros

• Cheapest bag here at $39.99
• Roomy semi-rectangular shape
• Two can zip together into a double

Downsides

• Heaviest and bulkiest bag on this list
• Too cold for shoulder-season nights near freezing
• Some owners report zipper problems

Check the KANYAK sleeping bag price on Amazon

How to read sleeping bag temperature ratings

• ISO comfort: the temperature at which a cold sleeper should be comfortable. Plan around this.
• ISO limit (lower limit): the temperature at which a warm sleeper can sleep curled up. Treat it as the floor.
• Extreme or survival ratings: not a sleeping temperature. Ignore them when choosing.
• Non-ISO ratings: brands that don’t use ISO testing may rate bags more generously. Compare comfort figures, and add a margin.
• Your pad matters: a bag rating assumes an insulated pad under you. A thin pad on cold ground makes any bag feel colder.

Sleep system checklist

• Sleeping bag rated at least 5°C (10°F) below the coldest expected night
• Insulated sleeping pad
• Dry base layer and socks kept only for sleeping
• Dry bag or pack liner for the sleeping bag
• Warm hat

Next, see how to pack a tent so your shelter and sleep kit fit in one pack.