Every 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. Here are eight of the best bags that will guarantee a cosy, comfortable kip from early spring, through summer, to late autumn.
Key features to look for in three-season sleeping bags
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 temperature ratings (eg the ‘Rab Sleep Limit’).
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 guides 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.
Want more warmth? 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.
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.
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; for example, if it has a higher fill weight (i.e. more down) inside the bag.
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.
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.
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.
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.
Packed size and weight: As you’ll be carrying it up hills and across landscapes, aim for a bag with the lowest weight and most compact packed size within your specific temperature and price range.
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) | Packed size 20x15cm (regular) | Sizes Small, regular, long
Deuter Exosphere -6°C £170
Super-stretchy is the best way to describe this synthetic sleeping. It features internal and external elastic chamber seams, which provide 25% expansion and contraction in the bag’s width. Why? So that the bag stretches with you when you toss, turn or shuffle at night, but then when you stay still the insulation is brought close to the body to eliminate cold spots. This body-hugging sensation is probably rather Marmite-y: you’ll either love it or hate it. Certainly it delivers a tight, narrow fit that some will find super-snug (akin to a baby being swaddled), while others might consider it too constricting. The price is very competitive (we found it for £99 online at Go Outdoors) and provides a decent 0°C comfort rating, thanks to the hefty 870g fill of synthetic insulation. Other features include the use of brushed fleece inserts inside the bag for a soft feel, extra water-repellency at the head and feet via a sturdier Dryzone shell, and Velcro closure to the adjustable neck baffle for a sealed-in feeling around the head. You also get an adjustable hood, full-length two-way zipper, added insulation in the cosy footbox and a compression sack.
Fill 870g of Deuter Thermo ProLoft synthetic insulation | Temp rating 0°C comfort, -6°C comfort limit | Weight 1370g (regular) | Packed size 33x19cm (regular) | Sizes Regular, slimline, long
A body-hugging, stretchy bag at an affordable price – but the cut and design won’t suit everyone.
Packed size 3/5 | Weight 3/5 | Features 4/5 | Performance 4/5 | Value 4/5
Overall score: 72%
Robens Icefall Pro 900 £180
The Icefall Pro features synthetic insulation, but you’d be forgiven for thinking this bag is full of lofty, high-grade down. The MicroThermo Ball insulation mimics the performance of down superbly, puffing out into a plump, thick and cosy haven. The interior is luxurious, courtesy of a whopping 900g fill of polyester clusters, and all-round warmth is enhanced by a good hood, well-padded neck baffle, two thick zipper baffles, and the box-wall construction. Rated 0°C for comfort, the temperature grade is very realistic and, anecdotally at least, the Icefall Pro 900 feels warmer than some bags with better EN/ISO ratings. The other striking feature is its central zip, which makes getting in and out easy, facilitates fine-tuned climate control, adds versatility (completely unzip to use like a quilt), and enables you to sit up and use your arms for chores like cooking or gear organisation. Price-wise, it’s a bargain, but there are downsides. It’s the heaviest on test, far from the most compact when packed away, and the synthetic insulation isn’t as premium as down. For beginner campers or price-conscious experts, however, this is an affordable, high-performing choice.
Fill 900g of 600 fill power MicroThermo Ball synthetic insulation (100% polyester) | Temp rating 0°C comfort, -5°C comfort limit | Weight 1395g | Packed size 42x18cm | Sizes One size
A cosily-insulated, fluffy synthetic sleeping bag at a great price – but it’s heavy and bulky.
Packed size 3/5 | Weight 3/5 | Features 4/5 | Performance 4/5 | Value 5/5
Overall score: 76%
Rab Ascent 700 £270
There is nothing particularly spectacular about this bag. No bells or whistles, or innovative designs and ingenious features. Instead it just focuses on doing all of the basics very well at a decent price, making it a great 3-season choice for the average UK wild camper. The down’s fill power is a slightly disappointing 650, but there’s a lot of it – 700g to be precise, which ensures a solid -2°C comfort rating. The adjustable hood is well-shaped with good coverage, there’s a thick and close-fitting neck baffle for sealing out the cold, and the Pertex Quantum outer fabric is more durable and tougher than the shells of many other bags. The mummy cut is quite wide, striking a nice balance between freedom of movement and a secure, warm feel. You also get a ¾-length zipper with anti-snag zip guard, internal collar, angled footbox, and the Nikwax down used is hydrophobic, meaning it retains heat better when wet. The Ascent 700 also comes with a compression stuffsack and cotton storage sack. At 1290g it’s on the heavy side but many will happily overlook this, content with reliable performance at a good price.
Fill 700g of 650 fill power duck down | Temp rating -2°C comfort, -8.5°C comfort limit | Weight 12900g (regular) | Packed size 40x27cm (regular) | Sizes Regular, extra long, women’s
A mid-range, affordable down sleeping bag that’s reliably warm – but Rab has more technical offerings.
Packed size 3/5 | Weight 3/5 | Features 4/5 | Performance 5/5 | Value 5/5
Overall score: 80%
Sierra Designs Cloud 800 20° £290
This sleeping bag is a maverick, adopting an innovative design that’s exceptionally comfortable. 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 delivering a sensation more akin to your bed at home. A big overlap between the comforter and the bag’s edge prevents draughts, while the zipperless design makes getting in and out easy. With 419g of 800 fill power down and a -3°C comfort rating, warmth is impressive for the price. It’s versatile too: on warmer nights, fling open the comforter and stick your feet out of the footwell vent for a less clammy night’s sleep. Underneath the body there’s no down (it usually gets squashed anyway, compromising the insulation), and instead there’s a sleeping mat sleeve. This quilt-inspired feature ensures excellent mat-to-bag integration and keeps weight down. The 15-denier shell adds quite a bit of weight (due to all the design features), the cut may be too roomy for some, and the quilt-like design makes a good mat essential. But these flaws are minimal, when all-round comfort and warmth is so impressive.
Fill 419g of 800 fill power DriDown | Temp rating -3°C comfort, -10°C comfort limit | Weight 880g (regular) | Packed size 38x19cm (regular) | Sizes Regular, long, women’s
A versatile, warm and extremely comfy bag with an innovative design – but the quilt-like approach won’t suit everyone.
Packed size 4/5 | Weight 4/5 | Features 5/5 | Performance 5/5 | Value 4/5
Overall score: 88%
NEMO Disco 15 £300
This bag is very roomy. If you’re a side sleeper, tummy sleeper, night-time shuffler, or someone who hates the claustrophobic cocoon of a mummy-style bag, it’s a great option: restful, spacious and non-restrictive. For some campers this will enhance comfort greatly (I loved the roomy cut during a wild camp); for others the excess space and reduced thermal efficiency might be a deal-breaker. Other cons include the use of 650 fill power down rather than a higher grade, the rather bulky packed size, and the weight. But there are numerous pros too. The contoured, spoon-shaped cut provides extra space at the elbow and knees for easy re-positioning, the in-built Thermo Gills provide venting and breathability when required, and the waterproof footbox is well-protected against condensation. You also get a full-length two-way zipper, adjustable hood, integrated pillow sleeve, and – best of all – an extremely plush collar baffle that gives a lovely tucked-in sensation. The -4°C comfort rating is impressive (although potentially a tad over-optimistic, considering the spacious dimensions) and the generous 625g fill weight certainly gives the bag a thick, warm feel. Side sleepers form an orderly queue.
Fill 625g of 650 fill power down | Temp rating -4°C comfort, -9°C comfort limit | Weight 1220g (regular) | Packed size 30x23cm (regular) | Sizes Regular, long, women’s
A spacious and fully-featured sleeping bag designed specifically for side sleepers – but has some flaws.
Packed size 3/5 | Weight 3/5 | Features 4/5 | Performance 5/5 | Value 4/5
Overall score: 76%
Mountain Equipment Firelite £420
Securing a comfort rating of -2°C but weighing in at just 770g, the Firelite is warmer than many bags over 1kg. This is achieved through a 469g portion of 800 fill power goose down, which feels reassuringly thick and should perform to the quoted temperature ratings. The extra 50-100g of fill, compared to other bags in this list, provides a nice warmth boost, and could make the difference on cold spring or autumn nights. This approach, however, results in a hefty price-tag and high weight. The Firelite’s ‘alpine’ fit strikes a nice halfway house – enough room for shuffling and movement, but not so roomy that there’s dead space and thermal efficiency is compromised. On the outer you get an ultralight Plasma 10-denier shell and a full-length zipper, while the slanted box-wall construction throughout the bag enhances overall warmth-to-weight. The adjustable hood works well, the six-baffle footbox is cosy, and the waterproof roll-top stuffsack is a great idea, meaning you don’t have to pack your compression sack in a separate dry-sack. Or, in other words, there’s very little to dislike with the Firelite.
Fill 469g of 800 fill power goose down | Temp rating -2°C comfort, -8°C comfort limit | Weight 770g (regular) | Packed size 25x17cm (regular) | Sizes Regular, long
A reliable sleeping bag with premium features and insulation – but it’s rather pricey.
Packed size 4/5 | Weight 4/5 | Features 5/5 | Performance 5/5 | Value 4/5
Overall score: 88%
PHD M.Degree 300 K Down Sleeping Bag £651
Wild camping the 299km Pembrokeshire Coast Path in six days during a cold spring week, this sleeping bag proved an absolute revelation: cosy, warm and unbelievably light. The weight-to-warmth ratio is achieved through the use of the highest quality 1000 fill power goose down. Such down is rare and, therefore, very expensive. The price-tag is somewhat eye-watering – but the quality is undoubted, with a voluminous, super-fluffy loft. PHD doesn’t publish EN/ISO ratings, citing flaws in the system, but instead states an in-house rating of -3°C. It’s tricky to be scientific about its accuracy, but certainly on Pembrokeshire nights hovering a few degrees above 0°C it kept me warm enough. The adjustable hood is good but not the plushest on test, and for colder nights a slightly heavier bag with a higher fill weight would be preferable. But for ultra-light, fast-hiking adventures, it hits the sweet spot with arrow-like precision. It weighs a remarkable 445g (standard size, no zip), but thanks to PHD’s made-to-order approach bespoke options are available: simply choose from numerous widths, lengths, zip orientations and optional extras. Other features include a 7-denier water-resistant shell, box-wall construction on top for maximum loft, and comfy oval footpiece.
Fill 1000 fill power goose down | Temp rating Typical operating temperature**** -3°C (in-house PHD rating)** | Weight 445g (standard size, no zip) | Packed size 21x13cm (standard) | Sizes** Lengths (short, standard, long and extra long), widths (slim, standard, wide, extra wide)
The 1000 fill power down delivers an incredible warmth-to-weight ratio – but it’s very expensive.
Packed size 5/5 | Weight 5/5 | Features 3/5 | Performance 4/5 | Value 3/5
Overall score: 80%