During the spring, summer, and fall seasons, a sleeping bag is intended to keep you warm and comfortable. The most effective sleeping bags are typically rated for temperatures between 20 and 40 degrees Fahrenheit (-6 to 4 degrees Celsius), and they are made to be used in moderately cold or warm weather, these are called three-season bags.

As well as considering the outside night-time temperature on a camping trip, it’s important to take into account your personal comfort levels. We’re all different and some of us are ‘cold sleepers’.

Women are more likely than men to sleep colder at night, largely explained by physiological differences, including, on average, lower muscle mass. Hormonal fluctuations will also affect women’s core body temperature at different times of the month and through the menopause.

best three-season sleeping bags

Fill type, construction, warmth, weight and packability are all important aspects to consider when choosing a sleeping bag.

Age makes a difference, too. Both men and women are likely to suffer a decrease in the body’s circulation capacity as we age, as the walls of our blood vessels lose their elasticity. When blood moves more slowly through the body, our extremities tend to feel the cold more quickly.

So, it’s worth paying close attention to the lower end temperature ratings – sometimes called the ‘comfort limit’ – as a rough guide to temperature performance. Look for zoned areas of warmth, too – in particular the foot box, hips, and hoods with baffles around the shoulder, neck and face.

In this comparative test of the best sleeping bags on the market right now we look at everything to make sure that you have the most informed decision possible when purchasing your next sleeping bag.

In case of interest, we’ve recently compiled a similar assessment of the best alternatives to sleeping bags and the best hiking boots too.

The best sleeping bags for 2023

The following list shows the best sleeping bags for men and women, all suitable for three-season camping. Each item has been extensively tested and reviewed by our expert gear team and rated for its performance, value, durability, feature set and the balance between weight and warmth.

  1. Gruezi Biopod Downwool Subzero 185 | €370 – Best sleeping bag 2023
  2. Rab Women’s Neutrino 400  | $400 / £400 
  3. Therm-a-Rest Parsec 20F/-6 | $499 / £430 Highly recommended
  4. Sierra Designs Women’s Night Cap 20 | $180 / £160 
  5. Kelty Women’s Cosmic Synthetic 20 | $110 / £90 
  6. Sea to Summit Ascent Acl-4 | $399 / £320 
  7. Robens Icefall Pro 900 | $200 / £190
  8. Nordisk Oscar -2° Curve | International shipping / £296
  9. Deuter Orbit -5° | International shipping / £115
  10. Mountain Equipment – Helium 600 | $469 / £280
  11. Alpkit Cloud Peak 300 | $130 / £110 | Best budget women’s sleeping bag
  12. Mountain Equipment Firelite | $700 / £500
  13. Rab Neutrino 600 | $475 / £440

How we tested the best sleeping bags

The products here were all assessed by Fiona Russell, Peter Macfarlane, Lucy Wallace & James Roddie

Fiona is a US size 8 (UK 10) and is 5 foot 6 tall. She is a cold sleeper. She walked and wild camped with the bags (and used the same inflatable sleeping mat) in the mountains and glens of the Scottish Highlands. To test the DWR (durable water repellent), she poured on water and applied a little pressure and movement. The product weights are taken from Fiona’s own digital scales.

Peter Macfarlane slept in the bags in the same woodland bothy and using the same sleep mat to achieve some consistency in judging the overall performance. Peter is six feet tall with a 44” chest and comments on fit are based on his sizing. Peter tested for water resistance to spills and condensation by applying clean water and light pressure. Weights are from his scales.

Lucy Wallace is 171cm tall with narrow shoulders. She sleeps cold, so likes a warm bag. Her bags were tested in winter and spring conditions in Scotland and the Lakes, both wild camping and in a campervan. Weights including stuff sack were measured on Lucy’s digital scales. 

James Roddie is 180cm tall with average-width shoulders. He tends to be a ‘cold sleeper’, and he has taken this into consideration. He tested the sleeping bags in a variety of conditions in the Scottish Highlands during the spring – in overnight temperatures ranging from around +2°C to +9°C. He weighed the sleeping bags (including stuff sacks) using his own digital scales.   

Gruezi Biopod Downwool Subzero 185 – Best sleeping bag tested

best three-season sleeping bags: Gruezi Biopod

  • Rating: 4.5/5
  • Price: €370 ( Buy now from Alpine Trek)
  • Weight: 2.31lbs | 1050g
  • Pros: warm when wet, innovative, comfortable
  • Cons: name is misleading

Shell: 20 denier 380T nylon (100% polyamide) Fill: 506g DownWool of 70% duck down (90/10, 650+ cuin) and 30% wool Construction: H chambers | Zip: two-way, curved, 3.4-length, whitened for night visibility | Length: 215 x 80 x 50 cm (for body heights up to 185 cm) | Rating: EN 23537: T Komfort: 2°C (36°F) | T Limit: -4°C (25°F) | T Extrem: -20°C (-4°F) | Sizes: one size, unisex.

This sleeping bag, which won best sleeping bag in The Great Outdoors Awards 2023, is filled with 70% duck down and 30% wool and is treated with an eco-friendly DWR. The overall weight is 1kg. Gruezi’s idea is that by adding wool to the down, it not only brings extra warmth but it also helps to draw moisture away from it, like some kind of natural dehumidifier. From our experience this really works.

In tests, it proved very comfortable, warm and not too heavy to carry – which is surprising given the wool content. The draught collar, hood and baffle construction prevented any cold spots and details like the pillow pocket, mini pocket for a headtorch or phone and the whitened zip (white makes it easier to spot at night) all proved very handy.


Therm-a-Rest Parsec 20F/-6

best three-season sleeping bags: Therm-a-rest Parsec

  • Rating: 4/5
  • Price: $499 / £430 ( Buy now from Alpine Trek)
  • Weight: 2.06lbs | 935g
  • Pros: Very warm for weight, three sizes available
  • Cons: Expensive

Fill: 470g 800FP Nikwax hydrophobic RDS down | Shell: 100% recycled nylon ripstop DWR | Construction: box wall | Zip: ¾-length two-way YKK anti-snag | Length: 80inch | 203cm (regular) | Rating: comfort 0°C, limit -6°C | Sizes: small, regular, long | Men’s version: no, unisex

Highly Commended in The Great Outdoors Awards 2023, the Therm-a-Rest Parsec -6 is a high-quality down sleeping bag and we tested it in some very soggy conditions. It has nice details such as a cosy pocket for feet in the bottom, a large zipped pocket on the outside, and removable straps underneath. The mummy hood is deep and luxurious, and the neck baffle isn’t adjustable. The bag is not available in men’s and women’s versions, but Therm-a-Rest produces three sizes. The regular size is generous in length (203cm) and fairly narrow (157cm girth), and a reasonable fit overall. The shell and liner are made entirely from recycled materials and filled with Responsible Down Standard down.

Our judges in The Great Outdoors Awards agreed that theTherm-a-Rest Parsec 20F/-6 ticks all the right boxes for a sleeping bag, being “warm and comfortable, light and with some useful features and materials”.

Read Lucy’s full review on the Therm-a-Rest Parsec 20F/-6

Rab Women’s Neutrino 400

RAB 400 sleeping bag review and rating


  • Rating: 4.5/5
  • Price: $400 / £400 ( Buy now from LD Mountain Centre)
  • Weight: 1.8lbs | 849g
  • Pros: Light and warm
  • Cons: Expensive, snug fit for taller women

Fill: 400g 800FP Nikwax hydrophobic RDS European goose down | Shell: 20D Pertex Quantum recycled nylon ripstop | Construction: trapezoidal box wall | Zip: ¾-length YKK two-way anti-snag | Length: 79inch | 200cm | Rating: comfort -1°C, limit -7°C | Sizes: one | Men’s version: yes

Chosen as our tester’s Best Buy in their comparative review of sleeping bags, Rab’s Neutrino 400 sleeping bag, which was launched in 2022, is an excellent option for backpacking, offering lightweight warmth and some handy details. It features chevron-shaped baffles, an improved drawcord system, a small pocket inside the hood, and a snag-resistant two-way zip. The women’s version is smaller than the men’s, but it is narrower at 156cm girth. The bag is filled with European goose down, certified by the Responsible Down Standard, at Rab’s factory in the UK. The tough Pertex Quantum used both inside and outside the bag is made from recycled materials and is fluorocarbon-free. It is a premium down bag for lightweight use in the shoulder months and even winter.

Read Lucy’s full review of the Rab Women’s Neutrino 400

Sierra Designs Women’s Night Cap 20

Therm-a-Rest Parsec sleeping bag review.


  • Rating: 3.5/5
  • Price: $180 / £160 (Buy now from Amazon)
  • Weight: 3.5lbs | 1626g
  • Pros: Versatile, especially for warm sleepers
  • Cons: Zipless design can lead to draughts

 Fill: 1276g recycled Sierraloft Eco Synthetic | Shell: 20D recycled polyester Construction: synthetic fill | Zip: none | Length: 74inch | 188cm | Rating: comfort +1°C, limit -5°C | Sizes: one | Men’s version: yes

Sierra Designs has pioneered innovative zipless bag designs, such as the Nightcap 20. The wrapover shape creates versatility for warm sleepers who like to vent through the night and allows for spreading out a bit if needed. The drawback is that it can fall open with too much movement, leading to draughts. The bag includes a sleeping mat sleeve on the base and a neck baffle, and the Eco Synthetic fill is made from recycled water bottles and the shell is recycled. Overall, it is clever and warm, with a smaller environmental footprint than many other synthetic bags, and some will love the versatile comforter system.

Read Lucy’s full review on Sierra Designs Women’s NightCap 20

Kelty Women’s Cosmic Synthetic 20

Kelty Women’s Cosmic Synthetic 20 sleeping bag review

  • Rating: 3/5
  • Price: $110 / £90
  • Weight: 4.1lbs | 1856g
  • Pros: Good value, warm
  • Cons: Heavy, not very compressible

 Fill: 1300g CirroLoft | Shell: 380T nylon taffeta | Construction: synthetic fill | Zip: Kelty’s own brand ¾-length two-way | Length: 74inch | 188cm | Rating: comfort -4°C, limit -11°C | Sizes: one | Men’s version: yes

The Cosmic 20 synthetic sleeping bag is a good value for warmth and overall price. It features generous but non-adjustable front and back neck baffles, and a drawcord to keep heat in around the face. It is 188cm long and wide around the footbox, providing some wiggle room for side sleepers. It is heavy at 1856g, but Kelty’s proprietary CirroLoft synthetic fibres do feel stiff and bulky, and its minimum pack size is 41x25cm, making it best suited to car camping.

Read Lucy’s full review on Kelty Women’s Cosmic Synthetic 20

Sea to Summit Ascent Acl -4

Sea to Summit Ascent Acl -4 review


  • Rating: 4/5
  • Price: $399 / £320 ( Buy now from Alpine Trek)
  • Weight: 2.04lbs | 926g
  • Pros: Warm, packs down very small, hydrophobic down fill.
  • Cons: Expensive

Fill: 330g 750FP Ultra-Dry down | Shell: 20D ripstop nylon | Construction: side block baffle | Zip: 2-way, full-length on left, 2-way, 1/3-length on right | Length: 81inch | 205cm (regular) | Rating: comfort +2°C, limit -4°C | Sizes: regular, long | Women’s version: no

The Ascent is a mid-point between a mummy and a semi-rectangular bag. It has a generous lofting sack and an ultralight compression sack. It has 330g of 750 fill power Ultra-Dry hydrophobic down and Sea to Summit claims it can dry out 60% faster than untreated down. The hood is generous and can be tightened down. The bag has a zip on the right-hand side and a foot box ventilation zip, but its insulation did not extend along the length of the foot box zip. Overall, the Ascent is a very attractive option, warm, lightweight and suitable for a wide variety of conditions.

Read James Roddie’s full review on Sea to Summit Ascent Acl-4

Robens Icefall Pro 900

Robens Icefall Pro 900 review


  • Rating: 4/5
  • Price: $200 / £190 (Buy now from Amazon)
  • Weight: 3.2lbs | 1495g
  • Pros: Very warm and comfortable, versatile centre zip design
  • Cons: Heavy, long with no shorter option

Fill: 900g MicroThermo Ball 600FP polyester | Shell:  20D ripstop nylon | Construction: box wall | Zip: 2-way, near-full-length in centre | Length: 87inch | 220cm | Rating: comfort 0°C, limit -5°C | Sizes: long Women’s version: no

The Icefall Pro 900 is the warmest sleeping bag in this review due to its 900g MicroThermo Ball synthetic insulation. It is aimed at taller people and has a high waist drawcord to keep the warmth in. It has a zip in the centre of the bag, which makes getting in and out of the bag much easier and allows for even ventilation over the core. There is no side ventilation zip, but it is easy to undo the zip almost to the feet and use the bag like a quilt in warmer conditions. Whilst quite heavy and lacking a shorter version, the Icefall Pro 900 is a well-designed sleeping bag, particularly if you prioritize warmth and comfort.

Read James Roddie’s full review on Robens Icefall Pro 900

Nordisk Oscar -2° Curve

Nordisk Oscar -2° Curve review


  • Rating: 3.5/5
  • Price: International shipping / £296 (Buy now from Alpine Trek)
  • Weight: 2.07lbs | 940g
  • Pros: Lightweight, small size when packed away, 100% recycled synthetic filling made from recycled PET bottles
  • Cons: Expensive, zip-pulls small and fiddly

Fill: NorGuard S-PO s-core fibre | Shell: 7D ripstop nylon | Construction: offset double box wall | Zip: 2-way, 3/4-length on left | Length: 81inch | 205cm (large)  | Rating: comfort +4°C, limit -2°C | Sizes:  medium, large, extra-large | Women’s version: no

The Oscar -2° Curve is a lightweight and very packable sleeping bag. It is supplied with two different carry sacks, a dry-sack and an extremely lightweight bag made from the same ripstop nylon as the sleeping bag shell and lining. The shell and lining material feels soft, comfortable and very thin. The ‘curve’ shape of the bag is described by Nordisk as ‘the optimal balance between insulation and space’. The bag includes ventilation zips on both the right shoulder and foot box. The hood and draught collar are both easily adjusted, and the head felt nicely insulated on cold nights. It tested down to temperatures of +4°, and while other sleeping bags felt warmer in comparable conditions, the Oscar -2° Curve is a good option for three-season backpacking when size and weight are crucial considerations.

Read James Roddie’s full review on the Nordisk Oscar -2° Curve

Deuter Orbit -5°

Deuter Orbit -5° sleeping bag review


  • Rating: 3/5
  • Price: International shipping / £115
  • Weight: 4.03lbs | 1830g
  • Pros: Warm, affordable price, highly durable
  • Cons: Heavy, large when packed away

Fill: 900g high-loft hollowfibre | Shell: 50D Rec Pes ripstop | Construction: 2-layer | Zip: 2-way, full-length on left |Length: 81inch | 205cm (regular) | Rating: comfort +1°C, limit -5°C | Sizes: regular, large | Women version: yes

The Deuter Orbit -5° is a warm, affordable sleeping bag that is not aimed at lightweight backpackers. It is large and heavy, but it is well-insulated and has a thick baffle and draught collar to keep warm air in. The hood is warm, but it does not extend over the top/front of the head as much as it would like. The main two-way zip features a large pull, making it easy to find and use during the night. The anti-snag zip guard is an effective feature, as snagging zips is a common annoyance with sleeping bags. For general three-season camping, this is a warm and affordable sleeping bag, but it is large and heavy, and if carrying it whilst backpacking you will notice the weight quickly.

Read James Roddie’s full review on the Deuter Orbit -5°

Mammut Perform Down Bag

best three-season sleeping bags: Mammut perform down bag


  • Rating: 4/5
  • Price: $400 / £355 (Buy now from Alpine Trek)
  • Weight: 2.35 lb. / 1005g
  • Pros: Comfort, performance, price
  • Cons: Centre zip not for everyone, weight

Temperature comfort limit: 19.4°F / -7°C | Materials: 700 fill power ethically certificated duck down, polyester/nylon lining, nylon outer | Features: box wall construction, mummy shape, full-length two way centre zip, shoulder baffle, internal pocket, stuff and storage sacks. Comes with ear plugs and sleep mask. | Size: long | Women’s version: unisex

Chosen as Best Buy in a comparative review of the latest men’s sleeping bags, the Mammut Perform Down Bag comes with a different approach when compared to most other bags as it has a full length centre zip. The relaxed mummy fit allows for a good amount of movement, without there being lots of dead air space reducing efficiency. It’s very well insulated and the large internal pockets is big enough to store most items. The Mammut Perform is a brilliant bag for camping and offers a comfortable sleep.

Read Peter Macfarlane’s full Mammut Perform Down Bag review.

Mountain Equipment Firelite

best three-season sleepings bags: Mountain Equipment Firelite


  • Rating: 4/5
  • Price: $700 / £500 (Buy now from Alpine Trek)
  • Weight: 1.68 lb. / 764g (Regular)
  • Pros: Weight, comfort, performance
  • Cons: Price

Materials: 900 fill power ethically certificated goose down, nylon shell | Temperature comfort limit: 16°F / – 9°C | Features: slant box wall construction, mummy shape, stretch seams, full-length two-way zip, shoulder baffle, stuff sack and storage sack | Sizes: regular, long | Women’s version: yes

The Firelite is one of the lightest bags in this review, but it maintains a strong performance with very high quality down and light shell fabric. The weight of the bag means it’s great for longer hikes and high camps outside of winter. However all of this comes at a cost with it being the most expensive within the best mens sleeping bags test. 

Read Peter Macfarlane’s full Mountain Equipment Firelite review.

Rab Neutrino 600

best three-season sleeping bags: Rab Neutrino 600


  • Rating: 4/5
  • Price: $475 / £440 (Buy now from Alpine Trek)
  • Weight: 2.24 lb. / 1020g (Regular)
  • Pros: Comfort, performance
  • Cons: Weight

Materials: 800 fill hydrophobic, ethically certificated down; Pertex Quantum outer, nylon inner | Temperature comfort limit: 10°F / -12°C | Features: box wall construction, mummy shape, shoulder baffle, full-length two-way zip, internal pocket, stuff sack, storage sack | Sizes: regular, long, wide, long wide | Women’s version: yes

The Neutrino has got the joint lowest temperature rating in this comparative test with a comfort limit of 10.4°F (-12°C), making it perfect for winter expeditions. This means slightly more weight than others on test but the Neutrino is packed with features and comfort to make that extra few grams worth it. 

Read Peter Macfarlane’s full Rab Neutrino review.

Mountain Equipment women’s Helium 600

Mountain Equipment women's Helium 600 best buy


  • Rating: 5/5
  • Price: $469 / £280 (Buy now from Alpine Trek)
  • Weight: 2.23 lb. / 1012g (Long)
  • Pros: Warmth, attention to detail, female-specific
  • Cons: Incorrect weight

Materials: 700 fill power 90/10 duck down; shell and lining: 100% recycled 20D nylon | Temperature: ‘Good Night’s Sleep’ temperature 18°F / -8°C  | Features: women’s Alpine fit with zoned EXL system, slanted box-wall baffles throughout, five-baffle anatomically shaped hood, four-baffle anatomically shaped and offset foot-box, choice of regular left or right zip or left long zip, neck collar with Lode Lock closure, waterproof roll-top stuff sack, storage cube | Sizes: regular (maximum user height 170cm), long (185cm) | Men’s version: yes

Mountain Equipment have made some big claims when it comes to their Helium series of sleeping bags. There are a wide abundance of features, from the choice of two lengths and zoned system that encloses the bag around your body to cut out dead air space. The 600 is reasonably priced and lightweight but not at the expense of comfort which is why we’ve given it our best buy award.

Read Fiona Russell’s full Mountain Equipment Helium 600 Women’s review.


What makes the best sleeping bag for you?

1. Insulation: down versus synthetic

Sleeping bags use either down or synthetic insulation. Down fill is lighter and warmer for its weight and packs smaller, but loses performance when wet.

It comes in different qualities and fill weights, which affects performance and price. Synthetic fill is less compressible for packing but retains performance when wet.

2. Temperature ratings

In addition to the brands’ own temperature usage recommendations, it’s always worth checking sleeping bag temperature ratings. These are Comfort, Comfort Limit and Extreme.

Comfort indicates a temperature where you can expect a good undisturbed sleep; Comfort Limit is as low as you can expect a decent night’s sleep; and Extreme indicates the temperature where the bag should keep you safe but not comfortable enough for a night’s sleep. 

3. Construction

A down bag’s performance comes from its ability to allow the fill to ‘loft’ – to expand fully – trapping as much air as possible to retain body heat. Box wall construction aims to maintain an even density of insulation around your body but adds bulk and manufacturing expense; stitch-through construction is lighter and cheaper but allows cold spots.

4. Entry

Sleeping bags’ entry options range from full-length zips to half zips to no zips at all. Longer zips give easier access and let you cool off; shorter zips can get you a smaller pack size; zipless bags can be tricky to get into in small tents.

Main zips should have baffles to prevent heat loss.

5. Hood

Hoods vary greatly in style but can be vital on colder camps. The most basic are lightly insulated with a simple drawstring around your face whilst some are fully insulated and formed to give maximum protection.

6. Shoulder baffle

There is often an internal baffle that can be tightened around your shoulders to trap the warm air inside the bag. Easy adjustment of this feature is important.

7. Sleeping bag Fit

Most bags have a tapered ‘mummy’ shape, being widest at the shoulders and narrowing down to the foot.

Female and male bag designs account for different body shapes, and improves thermal efficiency by removing dead space. The amount of taper varies and can affect user comfort depending on your natural sleep position.

8. Footbox

Good footboxes are shaped to accommodate your feet whilst allowing insulation to fully loft to maintain warmth.

9. Pack size & weight

In the hills a compact, lighter bag will make life easier; for campsite use a heavier, bulkier bag may be less of an issue.

10. Additional sleeping bag features

Some bags have pockets, useful for keeping camera batteries warm or stashing a headtorch where it’s handy.