Best Three-Season Sleeping Bags 2023 | Warm, Cosy And Comfy Sleeping Bags For A Good Night's Sleep In The Great Outdoors - Outdoors Magic

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Best Three-Season Sleeping Bags 2023 | Warm, Cosy And Comfy Sleeping Bags For A Good Night’s Sleep In The Great Outdoors

Our pick of the best sleeping bags for camping, hiking and backpacking, with a range of cosy and durable options for warm or cold weather

The best three-season sleeping bags are essential bits of kit for spring, summer and autumn nights in the great outdoors. Choosing the right bag will help guarantee that you stay warm while camping. Plus, unzipping your tent to enjoy an epic view from the warmth of a cosy sleeping bag is one of life’s great pleasures.

But buying one can be a bewildering task. To help you pick the right bag, think about when and how you’ll use it. Will you be backpacking or car camping? And do you need a bag for warm summer nights, or cooler spring and autumn seasons? Also consider how your sleeping bag works with your pack, tent and sleeping mat. This guide will help you find the best three-season sleeping bag for your needs, with versatile options for different weather conditions.

Sleeping Bag Temperature Ratings Explained

To compare the warmth of different bags, look at their temperature ratings. Many sleeping bag brands use a standard rating. This is usually given as three figures: a comfort, limit and extreme temperature rating. The comfort rating is defined as the temperature at which a ‘standard female’ can sleep comfortably. The limit is the temperature at which a ‘standard male’ will be able to sleep without waking. Extreme is the temperature at which a ‘standard female’ can remain for six hours without risk of hypothermia. It’s not a perfect system, as we all differ in shape, size and how much we feel the cold. The figure you need to consider most is the limit rating. Most of the bags featured here have a limit rating of around -5ºC.

Down Or Synthetic Sleeping Bags?

Weight is another critical factor. The ideal three-season sleeping bag will weigh around a kilo. Weight is largely dictated by the materials used, especially the insulation. This will be either goose or duck down, or a synthetic fill. For its weight, down is the warmest, lightest and most packable option. Its main disadvantage is that if it gets wet, it loses its insulating properties. Synthetic sleeping bags are heavier and bulkier but also cheaper, and they will still insulate when wet. So if you’re on a tight budget or go camping in damp conditions, a synthetic bag is a good choice.

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The performance gap between down and synthetic insulation is narrowing, however. Modern down is sometimes treated with a DWR (durable water repellent) that means it still insulates even when wet, while innovations in synthetic insulation are getting closer to mimicking the properties of down, making them lighter and warmer.

Down is comprised of the fine feathers of geese or ducks. It is a natural product that can have ethical concerns, though all the sleeping bags featured here use only responsibly sourced down.  Down quality is indicated by fill power (FP). The higher the number, the better quality the down. So a sleeping bag filled with 600FP down will require more down fill to generate the same warmth as a higher quality 800FP bag. That means the 800FP bag will be lighter and more packable – but also more expensive.

The most common sleeping bag for backpacking is a ‘mummy’-style bag. These are designed with a close-fitting hood and footbox to maximise warmth. Your bag should feel snug without being restrictive. Many sleeping bags come in different lengths for taller and shorter campers. Others are cut to fit typical body shapes. There are also dedicated men’s and women’s versions. When it comes to features, look for a full-length zip as well as baffle construction. This means the sleeping bag is filled in sections, which stops the insulation migrating inside the bag and causing ‘cold spots’.


The Best Three-Season Sleeping Bags

The sleeping bags in this round-up are primarily intended for three-season use; that is, for hiking, backpacking and camping in spring, summer and autumn. They range from lightweight down bags – ideal for fastpacking – to bulkier, synthetic options that are better suited to car camping.

  • Therm-a-rest Parsec -6 / 20F – Best Three-Season Sleeping Bag
  • NEMO Forte
  • Vaude Meglis Eco 700 Syn
  • Montbell Seamless Down Hugger
  • Rab Alpine Pro 600
  • Rab Neutrino Pro 400
  • Mountain Equipment Firelite
  • Gruezi Biopod Downwool Ice 185
  • Kelty Cosmic Down
  • Therm-A-Rest Questar
  • Jack Wolfskin Smoozip -5
  • OMM Mountain Raid Sleep System


BEST BUY: Therm-a-rest Parsec -6 / 20F

Price: £306
Weight: 810g
Best for: Backpacking, fastpacking
Key attributes: Responsibly made, excellent warmth-to-weight, handy details

With three different bags designed for use in the different seasons, and three different lengths available too, the Parsec range is undoubtedly versatile – there really is something for everyone here. The 20F / -6C model was the one deemed by our Test Team as being the best for three-season backpacking, bringing lightweight warmth that will see backpackers through all but the coldest of nights from the start of spring to the end of autumn.

We chose this as our Best Buy sleeping bag because it ticks just about every box that our reviewers look for. At 810g it’s light and it’ll also pack down to a size not that much bigger than a Nalgene bottle. But it’s also very warm too, all thanks to its 800 fill power down that’s contained in box wall baffles (the best form of baffle construction in terms of heat efficiency).

Then there are the eco credentials as well. The down, for instance, is all certified by the Responsible Down Standard to ensure the waterfowl in the supply chain were treated well and the nylon used for the shell and lining is made from 100% recycled nylon. No eco-hazardous PFCs are present here either.

Finer details include the Nikwax Hydrophobic Down Treatment, the impressive snag-free zipper and the super cosy foot warmer pocket. Plenty to like then.

Full Specifications

Available in warmer and cooler temperature ratings / available in three lengths / GRS-certified 100% recycled fabrics / Responsible Down Standard Certified / Nikwax Hydrophobic treatment / 800 fill power down / box wall construction / YKK zips / quilt and blanket loops / comfort rating: 0ºC comfort limit: -6ºC / extreme: -23ºC / packed size: 18 x 21cm.

Check out our full Therm-a-rest Parsec -6 / 20F review



NEMO Forte

Price: £210
Weight: 960g
Best for: Backpacking, lightweight adventures, side sleepers
Key attributes: Great value, sustainable fill, innovative design

Unlike most technical sleeping bags, which tend to be mummy-shaped, the Forte employs an unusual Spoon shape, which flares at the elbows and knees. This extra room is designed to allow side sleepers to shift positions comfortably throughout the night.

It’s available in men’s and women’s fits, in both regular or long lengths, and two temperature ratings too. All the bags are stuffed with warm but hard-wearing Primaloft RISE synthetic fill, encased in a ripstop shell and a soft taffeta lining. The fill is also made from 80% post-consumer recycled polyester.

The Forte 20 is rated with an ISO lower limit of 20°F or -6°C, so it ought to keep you warm even if temps dip just below freezing. That makes this a decent bag for three-season campsite-style camping. It’ll also work well for most wild camping adventures from spring through to autumn, though admittedly, things might start to get a little chilly if you’re high in the hills.

Full Specifications

Spoon shape design / men’s and women’s fits / regular and long lengths / two temperature rating options / Primaloft RISE synthetic fill (80% recycled polyester) / ripstop shell / taffeta lining / ISO lower limit of 20°F or -6°C / pack size: 29 x 23cm / bluesign system partner company / zero waste manufacturing / off-set carbon footprint / full-length two-way zipper / full-length draught tube / external draught collar / water resistant footbox / integrated pillow pocket / two zipped vents.

Check out our full NEMO Forte sleeping bag review.



Vaude Meglis Eco 700 Syn

Price: £160
Weight: 1,200g
Best for: Eco-conscious campers
Key attributes: Impressive planet-friendly credentials

The Meglis Eco 700 Syn is an ISPO Gold Award winning sleeping bag from Vaude. Probably the most game-changing and revolutionary sleeping bag we’ve ever come across, this innovative bit of camping kit is a massive great big, zero-gravity, leap into the future. We like it. We like it a lot.

If you’re doing some trekking and want a sleeping bag that’s going to show the world how serious you are when it comes to looking after the environment, look no further than the Vaude Meglis Eco 700 Syn. This sustainably produced, and surprisingly warm, sleeping bag will serve you well on your multi-day hiking missions.

Not one for your midwinter camping holiday in Siberia maybe, the three-season Meglis Eco 700 Syn will still do a job for you in more scenarios than it won’t. It has a temperature comfort of 2 °C, a temperature limit of -3 °C, and a temperature extreme of -20 °C.

Because of the materials used, the Meglis Eco 700 Syn is quite possibly the most environmentally friendly sleeping bag in existence. The inner and outer fabric is 100% recycled polyamide, while the guts of it contains a mixture of 70% Primaloft Silver Insulation (bringing its warm-when-wet qualities) and then 30% Kapok. Kapok, for those not in the know, is a tree found in southern Asia and the East Indies that produces little pods which contain a cotton-like material inside. For a number of years it has been used for mattresses and stuffed toys but companies are starting to find new ways to create yarns from it, with Vaude being the latest. They’ve managed to turn it into their own natural and biodegradable alternative to down and the results are impressive.

Full Specifications

Face fabric: 100% recycled polyamide / lining: 100% recycled polyamide / insulation: 680g of synthetic fill (70% Primaloft Silver insulation, 30% Kapok) / comfort rating 2ºC / limit rating -3ºC / extreme rating -20ºC / pack size: 40 x 24cm.

Check out our full Vaude Meglis Eco 700 Syn



Montbell Seamless Down Hugger

Price: From €499
Weight: 541g
Best for: Fastpacking, ultra running, orienteering
Key attributes: Exceptionally lightweight, totally windproof

Designed for three-season use and weighing just 541g, this sleeping bag should really appeal to those who are after that perfect warmth-to-weight ratio where the right balance is struck between comfort in the day, thanks to a low weight to carry, and comfort during the night. It’s the kind of item that lightweight backpackers, fastpackers, mountain runners and orienteers should really benefit from.

With this model, there are no chambers and there’s no stitching (hence the seamless in the name), with the down instead prevented from moving around too much within the walls of the bag by a unique ‘Spider Baffle System’. This is essentially a web-like layer that traps down feathers, ensuring that the fill is never able to fully migrate from one area of the sleeping bag.

On top of all that (quite literally), Montbell has used Gore’s new(ish) Infinium fabric for the shell. This is basically the next gen version of their Windstopper fabric. It’s super lightweight, highly water resistant (but not waterproof), totally windproof and has a lovely bit of stretch to it. It’s top grade stuff that you only really see in the best of sleeping bags out there.

The bag has a fill power of no less than 900. That basically means super high loft and thermal efficiency. The comfort rating is 4℃ and the lower limit is -1℃. With that in mind this probably won’t be warm enough for every single night through early spring and late autumn – not in Britain anyway – but for the milder days in those seasons it’ll be fine.

Full Specifications

Face fabric: Gore-Tex Infinium Windstopper 13d Ballistic Airlight nylon ripstop / lining: 7d Ballistic Airlight nylon / insulation: 900 fill power down / comfort rating 4ºC / limit rating -1ºC / pack size: 28 x 14cm.

Read our full Montbell Seamless Down Hugger



Rab Alpine Pro 600

Price: £300
Weight: 1173g
Best for: Wild camping, long-distance hiking
Key attributes: Warm, lightweight, weatherproof

A lightweight but weatherproof three-season sleeping bag that is actually warm enough for year-round use, the Rab Alpine Pro 600 is a real workhorse and a versatile option for mixed weather conditions. It pairs a Pertex Quantum Pro face fabric with DWR-treated 650FP duck down fill, giving it excellent all-round resistance to damp and moisture. The snug-fitting mummy style boosts warmth, as does the trapezoidal baffle construction. It’s a supremely well-made sleeping bag that promises to keep you cosy whether huddled on an alpine bivvy or backpacking a long-distance trail anywhere in the UK.

Full Specifications

Face fabric: Pertex Quantum Pro 20d 100% nylon / lining: 20d 100% nylon / insulation: 650 fill power duck down / comfort rating -3ºC / limit rating -10ºC / extreme rating -29ºC / pack size: 31 x 22cm.

Check out our full Rab Alpine Pro 600 review


Rab Neutrino Pro 400

Price: £345
Weight: 830g
Best for: General camping, campervanning
Key attributes: High quality design, 800 fill power, durable face fabric

Rab is a company with a great heritage in sleeping bags, and the Rab Neutrino Pro 400 is a well-proven down three-season sleeping bag. It offers a good balance between warmth and weight. The overall design and construction is of extremely high quality. The fill, meanwhile, is comprised of 800FP responsibly-sourced goose down, with a Nikwax water-repellent coating. Like other Rab bags, it uses a Pertex Quantum Pro face fabric to provide durability, breathability and added water resistance. The mummy style cut incorporates a well-designed foot box and a snug hood. On test we did find the hood drawcords a little confusing to operate. Overall, however, this is a warm and cosy sleeping bag for varied conditions throughout the UK and beyond.

Full specifications

Face fabric: 20d Pertex Quantum Pro 100% nylon / lining: 20d 100% ripstop nylon / insulation: 800 fill power goose down / comfort rating -1ºC / limit rating -7ºC / extreme rating -25ºC / pack size: 18 x 27cm.



Mountain Equipment Firelite

Price: £420
Weight: 770g
Best for: Backpacking, alpinism
Key attributes: 800 fill power, impressive warmth-to-weight, good features

The Firelite is an ultralight down sleeping bag designed for backpacking and alpinism. It uses high-quality, responsible-sourced 800FP goose down, which means it offers excellent warmth for weight while remaining very compressible. The bag’s comfort rating is 0ºC with a limit rating of -6ºC, but it is a warm bag, and Mountain Equipment’s own ‘Good Night’s Sleep’ rating puts it at -9ºC, which we’d say is accurate. The snug ‘Alpine Fit’ is space-efficient, minimising cold spots, while the construction utilises a ten denier Plasma face fabric that is lightweight and very breathable. The lining is made of the same material and feels very soft against the skin. The zip comes high up around the face, and a single drawcord pulls in around the head effortlessly.

Once you’re in, you feel cocooned against the world – in part because of the innovative elasticated baffles that eliminate dead space. Clever stuff. There’s no denying that the price is high, but it is commensurate with the quality. This is an excellent three-season sleeping bag from one of the best manufacturers in the business.

Full specifications

Face fabric: 10d plasma 100% nylon / lining: 10d plasma 100% nylon / insulation: 800 fill power goose down / comfort rating 0ºC / limit rating -6ºC / extreme rating -24ºC / pack size: 21 x 25cm.



Gruezi Biopod DownWool Ice 185

Price: €390
Weight: 1400g
Best for: Camping in damp conditions
Key attributes: Innovative technology, effective in damp conditions

Blending 70% duck down and 30% wool, the idea behind Gruezi’s fill is that it solves the moisture problem that fully down filled sleeping bags have (while also offering a natural alternative to the fully synthetic options out there).

Even condensation in a tent can drastically reduce the effectiveness of a down sleeping bag when it comes to insulation. The main solution to this in the past few years has been to add a hydrophobic treatment from the likes of Nikwax. This, however, doesn’t permanently solve the problem. It needs to be reapplied and reapplied. 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.

Contained within a nylon outer and inner lining with v-shaped baffles, the DownWool mix really does just feel like normal down. There’s certainly none of that itchiness we often associate with wool products and, at 1,400g, the warmth-to-weight ratio of the Biopod DownWool Ice 185 is decent too.

Other details on the Bipod Downwool include an innovatively shaped front zip that curls over the top of the bottom (enabling you to stick your feet out, if you’re overheating); a zipped pocket on the outside to keep a headtorch or your phone;  and then a Velcro sealed pocket on the inside also. There’s also a fabric flap where you can insert a pillow (or your down jacket).

Full specifications

Face fabric: 100% polyamide / lining: 100% polyamide / insulation: 70% duck down and 30% wool / comfort rating -1ºC / limit rating -8ºC / extreme rating -26ºC / pack size: 23 x 25cm.

Read our full Gruezi Biopod Downwool Ice 185 review



Kelty Cosmic Down Bag

Price: £130
Weight: 1.19kg
Best for: Campsite camping, long-distance backpacking
Key attributes: Excellent value, responsibly-sourced down and PFC-free fabrics

Available in 0, 20 and 40° Fahrenheit ratings (-17, -6 and 4 degrees Celsius respectively), the Kelty Cosmic is great for warm-weather campers and winter warriors alike. For us, the most versatile option is probably the Cosmic Down 20, which is a genuine three-season superstar. Stuffed with 550 fill power duck down in a soft yet hard-wearing 20-denier nylon taffeta shell, this bag offers both warmth and comfort, aided by a draught collar and chunky hood to help lock in the heat.

The Cosmic 20 is rated with an ISO Comfort of 32°F or 0°C and a lower limit of 21°F or -6°C, so it ought to keep you warm even if temps dip just below freezing. Unlike most low-cost rivals, this cosy down is exclusively sourced from Allied Feather + Down, which in turn is an RDS (Responsible Down Standard) certified supplier. The bags’ shell fabrics additionally only use environmental and health-friendly PFC-free durable water repellent (DWR) treatments.

The whole series also employs an innovative trapezoidal baffle construction resulting in greater thermal efficiency and fewer cold spots throughout. Other cool features include: a ‘natural fit’ footbox, an anti-snag two-way zipper design and a zipper draught tube to help to keep things extra toasty. 

Full specifications

-17, -6 and 4 °C options / ISO comfort rating of 0°C with lower limit of -6°C (Cosmic 20) / 550 RDS fill power duck down / fully traceable down / 20-denier, PFC-free nylon taffeta shell / pack size: 20 x 33cm / larger options available / trapezoidal baffle construction / cosy hood / roomy footbox / anti-snag two-way zipper design / internal stash pocket / lofty draught collar and zipper draft tube. 

Selected for our Green Gear Guide 2021/22 – Here’s our full Kelty Cosmic Down Sleeping Bag review. 




Therm-A-Rest Questar

Price: £240
Weight: 1100g
Best for: General camping
Key attributes: Syncs with sleeping mat, good balance between price and weight

Though best known for their sleeping mats, Therm-A-Rest also make an impressive range of sleeping bags, from ultralight options to comfortable base camp bags. The Questar is one of the brand’s mid-range three-season sleeping bags, striking a good balance betweeen price and weight. It’s a bit heavier than the other down bags here, because it uses 650FP insulation, meaning you need more down to reach its -6ºC limit rating compared to an 800+ fill power bag. Cleverly, however, the designers have placed more down on top and less underneath, where it would be compressed by bodyweight anyway. Removable ‘SynergyLink Connectors’ can attach the bag to your sleeping mat, ensuring that you – and the bag – stay in place, so the system works as it should. There are also loops to attach an additional down quilt, making this a versatile sleep system for winter use. The Questar also comes in three different lengths, though all seem to be fairly roomy.

Full specifications

Face fabric: 20d 100% ripstop polyester / lining: 20d 100% polyester taffeta / insulation: 650FP goose down / comfort rating 0ºC / limit rating -6ºC / extreme rating -24ºC / pack size: 23 x 36cm.




Jack Wolfskin Smoozip -5

Price: £110
Weight: 1890g
Best for: The casual camper
Key attributes: Superb value, clever zipper design

This synthetic sleeping bag will keep you warm down to around -5ºC, and offers great value for £100. It is the heaviest bag on test here, however, and is fairly bulky. For us, this puts it firmly in car or base camping territory – but for that sort of use, it’s a good option. Jack Wolfskin’s ‘Smoozip’ design eliminates the common problem of snagged zips. It utilises a unique ‘S-shaped’ zip that slides easily – though we did find that when drawing the zip up from the inside, it did snag a bit on the baffle.

The insulation is the brand’s own polyester Microguard, and this bag features extra fill around the torso and foot area to boost warmth. The lining and outer is made of a heavier 50d fabric, but is still soft to the touch. A nice detail is a soft fleece lining around the head, neck, arms and feet area; something missing from lighter bags. The fit is snug and cosy, with an easy-to-use drawcord and a close-fitting hood. As a cosy three-season sleeping bag for car camping, the Jack Wolfskin Ecosphere Re Smoozip is an excellent choice, especially for the price.

Full specifications

Face fabric: SoftTouch 50d / lining: SoftTouch 50d and Nanuk 150 fleece / insulation: microguard synthetic fill / comfort rating 1ºC / limit rating -5ºC / extreme rating -22ºC / pack size: 25 x 44cm.




OMM Mountain Raid Sleep System

Price: Jacket £190, Pants £150, Foot Pod £45 (Total: £385)
Weight: Jacket 390g, Pants 275g, Foot Pod 80g (Total: 745g)
Best for: Mountain marathons, adventure racing
Key attributes: Very lightweight, innovative approach

OMM don’t make outdoor gear like anyone else. That’s because much of the kit the brand produces is for specialist disciplines like mountain marathons and adventure racing, where the emphasis is on going fast and light. That’s also the ethos behind the Mountain Raid sleep system, which consists of an insulated jacket, trousers and a foot pod that combine together to create a ‘sleep suit’, eliminating the need to carry a sleeping bag.

Each piece uses PrimaLoft Gold Eco insulation, and though the sleep suit doesn’t offer the same level of warmth as a full three-season sleeping bag, for short overnight trips it is perfect. The jacket and the trousers are excellent standalone products, while the foot pod packs down to a size smaller than a tennis ball. It’s a versatile and innovative system, and we liked it a lot.

Full specifications

Face fabric: Point Zero fabric / insulation: PrimaLoft Gold Eco synthetic fill (60gsm top, 40gsm bottom)

Read our full OMM Mountain Raid Sleep Suit review.



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