We put the latest 3-season (spring to autumn) sleeping bags to the test and pick out the best. 

A three-season sleeping bag is a type of sleeping bag designed to provide warmth and comfort during the spring, summer, and fall seasons. The best three-season sleeping bags will typically be rated for temperatures between 20 and 40 degrees Fahrenheit (-6 to 4 degrees Celsius) and will be designed for use in weather conditions that are not extremely cold or hot.

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 10 best 3-season sleeping bags for 2023

The following list shows the 10 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 its balance between weight and warmth.

  1. Mountain Equipment – Helium 600Best three-season sleeping bag for women
  2. Rab Women’s Ascent 700
  3. Robens Serac 600
  4. PHD M.Degree 400 K custom-made
  5. Alpkit Cloud Peak 300Best budget women’s sleeping bag
  6. Mammut Perform Down Bag – Best men’s three-season sleeping bag
  7. Mountain Equipment Firelite
  8. Marmot Helium
  9. Rab Neutrino 600
  10. Thermarest Parsec – Best budget sleeping bag for men

How we tested them

The products here were all assessed by Fiona Russell and Peter Macfarlane

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.


Mammut Perform Down Bag – Best men’s sleeping bag

best three-season sleeping bags: Mammut perform down bag

  • Rating: 4/5
  • Price: $400 / £355
  • 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

The Mammut Perform Down Bag comes with a different approach when compared to the 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 our full Mammut Perform Down Bag review.

Mountain Equipment Firelite

best three-season sleepings bags: Mountain Equipment Firelite

  • Rating: 4/5
  • Price: $700 / £500
  • 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 our full Mountain Equipment Firelite review.

Marmot Helium

best sleeping bags: Marmot Helium

  • Rating: 3/5
  • Price: $479 / £375
  • Weight: 2.11 lb. 958g (Regular)
  • Pros: Comfort, price
  • Cons: No shoulder baffle

Materials: 800+ fill power ethically certificated goose down, Pertex Quantum 20D 100% nylon ripstop | Temperature comfort limit: 10.5°F / -12°C | Features: box wall construction, mummy shape, full length two way zip, internal pocket, stuff sack, storage sack | Sizes: regular, long | Women’s version: Xenon

The helium offers quite a neat fit without restricting movement, A well shaped foot box and warm hood which can be cinched with an external draw cord. There’s an easy to operate access zip, but this sadly snags on occasion, despite anti-snagging strips. Perfectly placed internal pocket allows easy access to torches and the like. There’s no shoulder baffle or drawcord for your chest making it difficult to completely seal yourself in.

Read our full Marmot Helium review.

Rab Neutrino 600

best three-season sleeping bags: Rab Neutrino 600

  • Rating: 4/5
  • Price: $475 / £440
  • 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 our full Rab Neutrino review.

Therm-a-rest Parsec -6

best three-season sleeping bags: Thermarest Parsec

  • Rating: 4/5
  • Price: $352 / £360
  • Weight: 1.99 lb. / 906g (Long)
  • Pros: Comfort, performance, price
  • Cons: Top bag design not for everyone

Materials: 800 fill power hydrophobic, ethically certificated down, nylon shell | Temperature comfort limit:  20°F / -6°C | Features: box wall construction, mummy shape, top bag design, shoulder baffle, full-length two-way zip, external pocket, stuff sack, storage sack | Sizes: small, regular, long | Women’s version: unisex

The Thermarest Parsec is the last bag on our list for the best sleeping bags for men and it’s one of our top performers. The Parsec is a top bag which means the Hood, foot box and the rest of the bag has insulation, however your back has very little. In turn this saves some weight and lets you customise your performance by having a mat to cover the missing areas. An effective baffle, roomy fit and external draw cords to cinch the hood means you’ll be getting a good nights sleep.

Read our full Therm-a-rest Parsec review.

Mountain Equipment women’s Helium 600 – best women’s sleeping bag

  • Rating: 5/5
  • Price: $469 / £280
  • 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 our full Mountain Equipment Helium 600 Women’s review.

Rab women’s Ascent 700

best three-season sleeping bags: Rab women's Ascent 700

  • Rating: 4/5
  • Price: $315 / £270
  • Weight: 2.74 lb. / 1243g
  • Pros: Warmth, attention to detail, female-specific
  • Cons: Weight, stuff sack

Materials: 650 fill power RDS-certified European duck down with Nikwax PFC-free hydrophobic finish; shell: 100% recycled 30D Pertex Quantum with PFC-free durable water repellency; lining: 100% recycled 20D nylon | Temperature: Rab sleep limit: 15°F / -9°C | Features: wide mummy shape, trapezoidal box wall construction, 3D-shaped neck collar, three-quarter long main zip with down-filled baffle, anti-snag zip insert and anti-snag internal zip guard, zipped internal stash pocket, angled foot box, drawcord stuff sack, zipped cotton sack with water-resistant base for home storage | Sizes: regular, 200cm long, user height 170cm maximum | Men’s version: yes

Next on our list of the best sleeping bags is the Rab Women’s Ascent 700. This sleeping bag is 50g lighter than the mens version due to a narrower shoulder and foot width. This light and cosy bag comes with a 15°F (-9°C) comfort rating, which should give you confidence even if you’re a cold sleeper. Zipped stash pockets at neck height are an appreciated feature, however we’d like to see a longer version of this bag available.

Read our full Rab Women’s Ascent 700 review.

Robens Serac 600

best three-season sleeping bags: Robens Serac 600

  • Rating: 3/5
  • Price: No U.S. shipping / £276
  • Weight: 2.38 lb. / 1080g
  • Pros: RDS-certified duck down, compressible stuff sack
  • Cons: Warmth, pack size

Materials: 600 fill power RDS-certified duck down 85/15; shell: 20D 400T nylon ripstop; lining: 20D 400T nylon taffeta | Temperature: comfort 19.4°F / -7°C | Features: mummy shape, face and neck baffle, full-length insulated zip, easy-adjust hood drawcord, loft expander design for increased warmth, shark-fin foot box, compression stuff sack, mesh storage bag | Sizes: short, 200x85x53cm, body length 175cm; other lengths: 195cm | Men’s version: unisex

This lightweight and fluffy sleeping bag from Robens, is not the warmest of bags on test making it hard to recommend when sleeping in any temperatures below freezing. A roomy width, with plenty of insulation in the neck baffle. A well worked foot area means it works well for people with larger feet. The Serac is definitely more of a luxurious choice designed for summer nights.

Read our full Robens Serac 600 review.

PHD M.Degree 400 K custom-made

best three-season sleeping bags: PHD M.Degree 400 K custom-made

  • Rating: 4/5
  • Price: $1044 / £882
  • Weight: 1.21 lb. / 550g (Standard custom-made)
  • Pros: Warmth, custom-fit and custom-made, weight
  • Cons: Price

    Materials: 1000 fill power European goose down; shell and liner: 7X ripstop nylon with DWR | Temperature: comfort 15.8°F / -9°C | Features: customised to suit customer size and needs; choice of four lengths and four widths; half and full-length zip, right or left, dual-construction design, oval-shaped footbox, various add-on options at extra cost including waterproof footbox/outer shell, stuff bag, mesh storage bag | Size: 16 sizes, depending on requests | Men’s version: unisex

Made start to finish in the UK the PHD M.Degree 400k sleeping bag is the most expensive bag that we have tested. The eye watering price can be explained as 95% of materials and components are sourced within Europe to minimise global transportation. The sleeping bag is also fully custom-made and fits like a glove when in use. It’s also the lightest and warmest bag that we’ve tried specifically made for people who demand the best warmth to weight ratio, however it comes at a costly price.

Read our full PHD M.Degree 400 K custom-made review.

Alpkit Cloud Peak 300

best three-season sleeping bags: Alpkit Cloud Peak 300

  • Rating: 3/5
  • Price: $130 / £110
  • Weight: 3 lb. / 1405g
  • Pros: Price, synthetic fill
  • Cons: Weight, pack size

Materials: 300gsm Thermolite T3E-ML Ecomade fill; outer fabric: 40D nylon 300T ripstop; lining: 20D polyester | Temperature:  Alpkit sleep comfort limit:  17.6°F / -8°C,| Features: synthetic polyester-based insulation using 35% recycled content, outer fabric with PFC-free water repellency, choice of left or right zip, insulated zip baffle, hood with neck baffle and adjuster, compression bag, machine-washable | Size: regular, 165cm to 180cm | Men’s version: unisex

The Alpkit Cloud Peak 300 is an ethical version for anyone looking for a goose down sleeping bag due to its synthetic fill. It offers a roomy width and length as well a neck baffle and thick zip baffle. However, this is a much heavier bag compared to the others we have tested which is something worth thinking about. For just over £100 it does score well on the weight to warmth ratio, so worth considering if you’re working to a budget.

Read our full Alpkit Cloud Peak 300 review.

What makes a good sleeping bag?

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, sleeping bags have three tested and certified outside temperature use ratings: 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.

Are sleeping bags washable?

Sleeping bags work most efficiently when they are clean. Dirt can impede their performance. However washing can also harm a sleeping bag and so should only be done when absolutely essential.

How easy it is to wash a sleeping bag depends on the fill. It’s not difficult with synthetic fills, quite a bit harder with down. Whichever type you have it’s worth taking precautions so that it doesn’t need washing very often.

  1. Sleep in clean clothes or a liner bag.
  2. Air your bag whenever possible. A few hours in the open can work wonders.
  3. Make sure your bag is stored loosely and there is air flow round it to prevent it getting musty.
  4. Spot clean dirty marks or sweat stains with a soft sponge and soap and water then wipe away any residue with a soft cloth.

Before washing any bag always check the care instructions.

Are synthetic sleeping bags washable?

Synthetic bags can be washed in a front-loading washing machine.

  1. Check the bag for any tears. Don’t wash the bag until these have been repaired.
  2. Run a wash cycle in the washing machine to remove any remaining detergent or fabric conditioner.
  3. Open zips and close Velcro tabs.
  4. Use non-biological detergent, pure soap, or a specialist product like Nikwax Tech Wash.
  5. Use a gentle, cool setting and a short spin. Heat can damage the bag.
  6. Tumble dry on a low heat setting or drape the bag over a clothes horse, ensuring strain isn’t put on the seams.

Are down sleeping bags washable

Washing a down bag takes time and requires care. Washing can be done by hand or in a machine. For drying a tumble drier is essential. The first steps are the same for machine and hand washing.

  1. Check the bag for any tears. Don’t wash the bag until these have been repaired.
  2. Open zips and close Velcro tabs.
  3. Use pure soap, or a specialist product like Nikwax Down Wash, Grangers Down Wash or Storm Down Wash. Don’t use detergent.

Machine Washing a sleeping bag

  1. Run a wash cycle in the washing machine to remove any remaining detergent or fabric conditioner.
  2. Wash on a gentle, cool setting (30°) with a low to medium spin speed.
  3. Rinse twice or more.

Hand Washing your sleeping bag

  1. Fill a very large tub – a bath is ideal – with warm water.
  2. Gently press the bag into the water until it’s saturated.
  3. Wash the bag carefully and gently with your hands. Don’t lift it out of the water.
  4. Rinse, rinse, and rinse again until the water is clear.

How to dry your sleeping bag

  1. Lift the bag carefully out of the machine or bath. To avoid putting a strain on the seams or baffles cradle it in your arms.
  2. Place the bag in a tumble drier.
  3. Add some tennis balls or similar as these will help break up the down and stop it clumping.
  4. Tumble dry on the lowest heat setting.
  5. Be patient! Drying can take several hours.
  6. Remove the bag from the drier often and gently break apart any clumps of down.