Every day of good adventure should end with a well-earned, restful sleep – not shivering until 3am in a woefully thin cocoon. That’s why finding the right sleeping bag is essential. A high-quality sleeping bag will guarantee a good night’s sleep. It’ll keep you warm, cosy and comfortable, and ensure you’re well-rested for the adventures ahead.
A 3-season sleeping bag is the most popular sleeping bag in terms of seasonality because it is designed for use between early spring and late autumn. But covering a broad seasonal range, there are naturally a great many types and styles of 3-season sleeping bag, from down-filled cocoons to synthetic duvets.
We've conducted out latest 3-season sleeping bag group test, including models from a range of price points and designs in order to establish which is best.
Key features to look for in three-season sleeping bags
EN/ISO temperature ratings: Sleeping bags are commonly graded by the EN/ISO standard, stating temperature ratings as ‘comfort’ (warm enough for the average female), ‘comfort limit’ (warm enough for the average male), and ‘extreme’ (you won’t die, but it’ll be very uncomfortable). To confuse matters, some brands publish their own in-house temperature ratings (e.g. the ‘Rab Sleep Limit’).
Fill power: Fill power is a rating system for down that measures compressibility and loft (fluffiness) – and gives an indication of its insulating properties. A higher fill power indicates better quality down and a greater warmth-to-weight ratio. Synthetic sleeping bags do not have a fill power rating but are graded in GSM (grams per square metre). The higher the figure, the thicker, heavier and warmer the insulation will be.
Fill weight: Fill weight is the amount of down in a bag, measured in grams. The higher the fill weight, the warmer a bag will be. This means that it’s important to check both the fill weight and fill power. A sleeping bag with only 650 fill power down can still be as warm as a bag with 900 fill power down, if it has a higher fill weight (i.e., more down) inside the bag.
Zip: A full-length zip makes it easier to get in and out of the bag and permits venting overnight if you’re feeling hot. A two-way zip works better for this.
Warmth-adding features: An insulated, adjustable hood can make a big difference in cold conditions, as will a cinched-in shoulder baffle (draught collar) to lock in heat. Extra baffles in a shaped footbed and a baffle over the main zip add warmth too.
Warmth: Choosing a bag you’ll be warm enough in is tricky. The comfort and lower limits are the best indicators, but they should be used as a guide only. You won’t necessarily be warm at the comfort limit temperature. If you tend to feel the cold badly, give yourself a buffer with the temperature ratings – for example, if you’ll be sleeping at 0°C, choose a bag with a comfort rating of -5°C.
Year-round use: The 3-season category covers a broad range of weights and temperatures. Some campers will opt for a warmer 3-season bag and use it year-round, but it’ll be too warm in spring and summer. Other campers will choose an ultralight 3-season bag ideal for summer, but they may feel too cold in the shoulder seasons. The keenest campers will need three products: an ultralight bag for spring and summer months, a warmer 3-season bag for colder nights, and a fully-fledged winter bag for sub-zero camps.
Packed weight and size: As you’ll be carrying it up a mountain, aim for a bag with the lowest weight and most compact pack size within your specific temperature and price range.
Size and shape: Most bags are available in different lengths and widths, as well as women’s specific models. Bags with a tapered ‘mummy’ style are narrower and cut out cold spots better, but can feel restrictive. Others have a roomier, more rectangular design, which some campers find more comfy.
Fill: Down or synthetic? That’s the dilemma. Choose down for a superior warmth-to-weight ratio, or synthetic for better value, easier maintenance and improved insulation when wet. For ethical reasons, make sure goose or duck down adheres to the Responsible Down Standard.
Construction: Most bags use box-wall construction to trap the fill inside brick-shaped pockets (baffles). Larger baffles give more space for insulation to loft, smaller baffles help stop the fill from spreading out.
The best 3-season sleeping bags
Therm-a-rest Hyperion 20F/-6C
Verdict: An excellent mummy-style sleeping bag for wild camping and backpacking, delivered at a superb weight.
If you’re serious about wild camping and backpacking, you can’t beat this sleeping bag. High quality, 900 fill power goose down delivers an EN/ISO comfort rating of 0 ̊C, despite weighing just 580g – so the overall warmth-to-weight ratio is top-notch. This is aided by the zoned design, with 70% of insulation placed on the top and sides (where you need it most) and 30% on the underside, while the box baffled construction further boosts loft and minimises cold spots.
Fill 360g of 900 fill power goose down | Temp rating 0°C comfort, -6°C comfort limit | Weight 580g (regular) | Pack size 20x15cm (regular) | Sizes Small, regular, long
Rab Neutrino 400
Verdict: A top-performing, fully-featured sleeping bag with improved eco credentials – but it’s pricey.
Pack size 4/5 | Weight 4/5 | Features 5/5 | Warmth 4/5 | Value 4/5
Overall score: 88%
Pros: Tried and tested design, excellent warmth-to-weight ratio, multiple sizes and versions
Cons: Pricey, narrow mummy-style won’t suit everyone
Rab’s Neutrino down sleeping bags have a longstanding and stellar reputation. Now featuring an eco upgrade for 2022, with PFC-free DWR treatments and more recycled materials (such as the 100% polyamide lining and recycled Pertex Quantum shell), the range is described by Rab as “lightweight in your packs and on the planet” with “exceptional packability and warmth-to-weight”. And it’s difficult to disagree.
The bags are fully-featured and well-designed, delivering a warm and comfy night’s sleep. There are 10 products to choose from, each filled with 800 fill power goose down.
The fill weight, however, increases in 100g increments from 200 to 900, with the number after each bag relating to its fill weight. Eight bags are in unisex versions, the 400 and 600 are available in women’s specific versions too, and the 300, 500, 700 and 900 are ‘pro’ versions with a more weather-resistant Pertex Quantum Pro shell.
The alpine-inspired Neutrino 400 is a particularly good option, with a tapered mummy design, chevron-shaped baffles, angled footbox, and -1°C comfort rating despite weighing just 775g.
Fill 400g of 800 fill power Nikwax hydrophobic goose down | Temp rating -1°C comfort, -7°C comfort limit | Weight 775g | Pack size 35x23cm | Sizes Regular, long, wide, long-wide, women’s
Robens Spire III
Verdict: A synthetic sleeping bag with impressive temperature ratings at a bargain price – but it’s heavy and bulky.
Pack size 3/5 | Weight 3/5 | Features 4/5 | Warmth 5/5 | Value 5/5
Overall score: 80%
Pros: Excellent value, impressive temperature ratings
Cons: Second heaviest on test, bulky, one size only
A -3°C comfort rating for the price of the Spire III is an utter bargain and difficult to beat, particularly considering the overall build quality, features and comfort you get here. We tested several other budget synthetic bags and often they felt cheap and poorly constructed, but the Spire III avoids this pitfall.
For price-conscious adventurers or beginner wild campers, it’s a good choice. If you’re willing to spend more, the Robens Icefall Pro 900 (Trail Magazine Best Value winner in 2021) is a superior synthetic bag, courtesy of the amazingly lofty, down-like MicroThermo Ball fill, but the Spire III still delivers a cosy sleep.
You get lots of nice features – interior valuables pocket, hanger loops, anti-snag ¾-length zipper, brushed lining, insulated footbox, adjustable hood and thick neck baffle – while the fill is a whopping 1150g of OneThermo polyester. These sheet-like layers of flat, low-profile, wadded insulation don’t feel as a plump or lofty as down, but in some ways feel more akin to your duvet at home – which some may find more comfy.
The Spire III is heavier than ideal, takes up a lot of room in your backpack and clearly isn’t as premium as more expensive models – but you really can’t complain at this price.
Fill 1150g of OneThermo synthetic insulation (100% polyester, 2x 200g/m2) | Temp rating -3°C comfort, -9°C comfort limit | Weight 1685g | Pack size 36x24cm | Sizes One size
Therm-a-Rest Parsec 20F/-6C
Verdict: A reliable sleeping bag with premium features and insulation – but it’s rather pricey.
Pack size 4/5 | Weight 4/5 | Features 5/5 | Warmth 4/5 | Value 4/5
Overall score: 84%
Pros: Lightweight, warmth-to-weight ratio, premium design, first-rate features
Cons: Expensive, comfort rating could be warmer for the price
With an EN/ISO comfort rating of 0°C but weighing just 810g, the Parsec 20F/-6C strikes a sweet spot between warmth and weight for 3-season use – truly one bag suitable for early spring to late autumn.
This is achieved through a healthy 470g portion of 800 fill power goose down, which feels reassuringly thick and should perform to the quoted temperature ratings. During two nights of bivvying on the Cleveland Way in mid-March, with nights just a few degrees above 0°C, the Parsec kept me amply warm and cosy. The down fill is Nikwax hydrophobic down, which absorbs 90% less water and dries three times faster than untreated down, according to Therm-a-Rest, ensuring wet weather won’t spoil your comfort levels.
Other first-rate features include Therm-a-Rest’s clever SynergyLink connectors, which strap your bag to your mat for an integrated sleeping system, and the super-cosy down-lined footbox. You also get everything else you’d expect: two-way YKK zipper (¾ length), ultralight 20-denier GRS-certified recycled nylon shell, plush neck and zipper baffles, adjustable hood, zoned insulation delivering warmth where you need it most, a tapered cut that is cosy without feeling restrictive, and both compression and storage sacks.
Fill 470g of 800 fill power Nikwax hydrophobic goose down | Temp rating 0°C comfort, -6°C comfort limit | Weight 810g | Pack size 21x18cm | Sizes Small, regular, long
Sierra Designs Night Cap 20°
Verdict: An innovative and well-priced synthetic bag with a zipperless design and clever ‘comforter’ – but the unique design might polarise opinion.
Pack size 4/5 | Weight 4/5 | Features 5/5 | Warmth 3/5 | Value 4/5
Overall score: 80%
Pros: Innovative zipper-less design, clever features, comfy, affordable
Cons: A tad heavy, style won’t suit everyone, risk of draughts, requires a good mat
This is the synthetic version of Sierra Designs’ Cloud 20° down bag. It’s a lot cheaper but 490g heavier and not as warm.
Like the Cloud 20°, the Night Cap 20° adopts an innovative design. There’s no zip, but the bag still opens wide thanks to a curved, wraparound ‘comforter’ – a duvet-like flap that pulls over your upper body. For some this will prove far comfier than a traditional bag. A big overlap between the comforter and the bag’s edge helps prevent draughts, while the zipper-less design makes getting in and out easy.
Two other eye-catching design features include a vent you can stick your feet out of if you get too hot, and a sleeve for housing your sleeping mat. The latter provides excellent mat-to-bag integration and ensures the insulation is thickest where you need it most, which is above the body rather than underneath it (where it’d just get squashed anyway and perform ineffectively).
Eco credentials are top-notch – the insulation is made from 100% recycled water bottles and the 20-denier shell is also recycled – while the roomy cut doesn’t feel restrictive. Not everyone will be drawn to the unique design, but some will simply love it.
Fill 1134g of SierraLoft Eco Synthetic insulation (100% recycled) | Temp rating 1°C comfort, -5°C comfort limit | Weight 1370g | Pack size 38x19cm | Sizes Regular, long
Marmot Hydrogen 30°
Verdict: An ultralight down sleeping bag with a first-rate hood and good design – but it’s expensive.
Pack size 4/5 | Weight 5/5 | Features 4/5 | Warmth 3/5 | Value 4/5
Overall score: 80%
Pros: Excellent hood, ultralight, 800 fill power
Cons: Low fill weight, expensive
There is a lot to like about this sleeping bag. With a 1°C comfort rating but weighing just 665g (the second lightest here), the warmth-to-weight ratio is impressive, striking a nice compromise for 3-season use in all but the coldest of spring or autumn days.
If reducing your pack weight is a priority, and you’re likely to be camping in warmer climes, the Hydrogen 30° is an excellent gram-saving choice. We were particularly impressed with the deep hood, which is comfy and can be sealed fully around your head for enhanced warmth. While the cleverly-curved two-way zipper – which extends over both shoulders, as well three-quarters of the way down one side – delivers good ventilation and flexibility to suit your sleeping style.
The goose down, featuring a Down Defender treatment for improved performance in wet conditions, has an 800 fill power and 320g fill weight. The latter is relatively minimalist, which probably won’t prove warm enough for nights hovering around 0°C or lower.
The shell is 20-denier Pertex Microlight and you also get a wraparound footbox, smoothly-curved baffles (designed to minimise down shifting), and a nifty internal pocket for a phone or headtorch.
Fill 320g of 800 fill power goose down | Temp rating 1°C comfort, -5°C comfort limit | Weight 665g | Pack size 31x15cm | Sizes Regular, long
Sea to Summit Spark SpII -2°C
Verdict: An ultralight, minimalist down bag for gram-counting campers – but the comfort rating is a little disappointing.
Pack size 4/5 | Weight 5/5 | Features 4/5 | Warmth 3/5 | Value 4/5
Overall score: 80%
Pros: Incredibly light, 850 fill power, excellent for long-distance treks
Cons: Disappointing comfort rating, risk of down separating, low fill weight
This sleeping bag is designed for the gram-counting, ultralight camper who still needs 3-season protection. Top quality 850 fill power goose down (the highest grade down on test) fills both horizontal and vertical baffles, delivering an EN/ISO comfort rating of 4°C and comfort limit of -2°C for just 490g. That’s easily the lightest bag here – ideal for long-distance treks where every gram counts.
For colder nights, the 4°C rating won’t be warm enough, though we’re a little surprised by that grading as the super-lofty, plush down feels warm enough for nights a degree or two colder. Alternatively, if you need more warmth, the Spark SpIII has a comfort rating of -2°C, weighs 665g, but of does cost more.
Slight concerns with the SpII include the lightness of the 10-denier shell and 7-denier liner, which must be handled with care, and the potential risk of the down separating within the rather wide baffles or ‘leaking’ out of the stitched seams. But there are lots of positives too. You get a contoured mummy design, half-length YKK zipper with press stud closure at the collar, cinchable hood, water-repellent treatment to the down, and ‘zoned’ construction for more insulation in the vertical baffles across the torso.
Fill 300g of 850 fill power Ultra-Dry goose down | Temp rating 4°C comfort, -2°C comfort limit | Weight 490g | Pack size 25x15cm | Sizes Regular, long, women’s (Flame)
Exped Comfort -5°
Verdict: A roomy, non-restrictive down bag with good freedom of movement – but its temperature ratings aren’t the best.
Pack size 4/5 | Weight 4/5 | Features 4/5 | Warmth 3/5 | Value 4/5
Overall score: 76%
Pros: Roomy design for taller and larger campers, not restrictive, good features
Cons: Only 700 fill power, disappointing comfort rating
Let’s start with the negatives. The 700 fill power down is the lowest grade on review, and the 2°C comfort rating is underwhelming and may prove a deal-breaker for some. Furthermore, the roomy cut won’t suit everyone’s sleeping habits, and the weight and price are middle-of-the-road.
But, if you’re a side sleeper, night-time shuffler or simply a larger-sized camper, this roomy sleeping bag might be your ticket to a better night’s sleep. There’s ample space for freedom of movement, particularly in the long and extra-long sizes, without allowing for cold spots or reducing thermal efficiency.
The all-round features and build quality are impressive. You get a large adjustable hood, thick draft collar, press stud closure around the neck (for sealing in warmth), cosy footbox, PFC-free 20-denier nylon shell, storage sack and stuffsack. Worthy of mention too is the full-length, two-way zipper which extends around the footbox, enabling excellent ventilation when required. When fully unzipped, it transforms the bag into an open, duvet-style cover.
A generous fill weight of 590g ensures the bag feels warm and cosy, despite the lower fill power rating, and in-use it feels a tad warmer than the 2°C comfort rating implies.
Fill 590g of 700 fill power duck down | Temp rating 2°C comfort, -4°C comfort limit | Weight 1140g | Pack size 26x17cm | Sizes Medium, long, extra-long
Deuter Orbit -5°
Verdict: A synthetic sleeping bag with a narrow cut at an affordable price – but it’s heavy.
Pack size 3/5 | Weight 3/5 | Features 4/5 | Warmth 4/5 | Value 4/5
Overall score: 72%
Pros: Affordable, seamless shell
Cons: Heaviest sleeping bag on test, narrow cut won’t suit everyone, bulky when packed away
Part of Deuter’s budget line of synthetic sleeping bags, the Orbit -5° is nothing spectacular. There aren’t any bells or whistles, or innovative design features to get excited about, but ultimately it does a good job at an affordable price. And for those on a budget, it might just hit the mark.
If you like a figure-hugging fit, the narrow cut of this bag will leave you as snug as a bug in a rug, while the 900g fill weight of polyester insulation is graded warm enough down to a comfort rating of 0°C. All of the normal features are present: adjustable hood, hanging loops, full-length zipper with anti-snag strip and integrated baffle, and Velcro tabs for sealing in warmth around the neck and collar baffle. Another nice touch is the absence of exposed seams on the outer, which removes the risk of insulation ‘leakage’ – a problem some bags are prone to.
The negatives of the Orbit -5° are quite obvious. It’s rather large when packed away and it’s far heavier than ideal – at 1740g it’s the heaviest here. Another alternative might be the super-stretchy Deuter Exosphere -6°C, which is 370g lighter but has the same temperature ratings.
Fill 900g of High-Loft Hollowfibre synthetic insulation (100% polyester, 2x 140g/m2) | Temp rating 0°C comfort, -5°C comfort limit | Weight 1740g | Pack size 48x25cm | Sizes Men’s, women’s (Orbit -5° SL)
Sleeping bag care and cleaning
Cleaning sleeping bags and storing them correctly when not in use are both very straightforward but need to be done correctly in order to enjoy many years of use. Head to our guide on cleaning and caring for insulated gear to find out how.