Group Tests and Best Buys

Best Three-Season Sleeping Bags 2025

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 sleeping 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.

The Best Three-Season Sleeping Bags of 2025

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 trips where weight and packed size aren’t so important.

Best Overall Three-Season Sleeping Bag: Therm-a-rest Questar 0F/18C
Best Lightweight Three-Season Sleeping Bag: Montbell Seamless Down Hugger
Best Synthetic Three-Season Sleeping Bag: Snugpak Softie 6
Best Value Three-Season Sleeping Bag: Kelty Cosmic Down 20
Best Sustainably-Made Three-Season Sleeping Bag: Nemo Forte 20

The Expert

I’m Will, I’m the editor of this site and I’ve been reviewing outdoor gear on a professional basis for well over a decade now. In that time, I’ve served on all of the major outdoor industry juries and I’ve hiked and run thousands of miles. Whether I’m long distance walking or trail running, most of my outdoor adventures involve wild camping. There was the time, for instance, when I spent 63 days straight wild camping around the perimeter of Wales. I also spent 23 nights fastpacking over all 189 of Wales’s mountains.

How We Tested Them

I was responsible for testing all of the sleeping bags in this round-up and I also tested countless others that didn’t make the cut. I’m 5 foot 10, have an average build and I’d say that I’m a neutral sleeper – I don’t sleep overly hot or cold. All of these bags were used in conditions between spring and autumn. As a backpacker, the warmth-to-weight ratio was a big factor in my assessment of each sleeping bag. Also, I spend a lot of time in wet conditions, so I looked for sleeping bags that can handle a bit of moisture too.

1. Therm-a-rest Questar 0F/-18C

Picked as the best overall three-season sleeping bag in our tests

On the right, Will using the Questar during an October in Scotland.

Price: £380
Weight: 1.21kg
Key attributes: excellent warmth-to-weight, neat design details, wide cut
Temperature rating: comfort rating: -10ºC comfort limit: -18ºC
Length: 185, 203 or 215cm
Fill type: down

This is a very cosy sleeping bag with excellent loft. We found that it can stretch into winter well but its optimum range is from early spring through to late autumn. During our tests with this, we slept in it when temperatures had dipped below freezing and it performed just as we wanted it to, providing a warm night’s sleep with plenty of space to move around too.

There are lighter and warmer sleeping bags out there but they’ll come with big price tags. This, on the other hand, provides an excellent balance between warmth, a low weight and also price. It has some useful details and clever innovations too, including a fit that’s designed for all kinds of sleeping positions and two straps for attaching a sleeping mat. There’s also a brilliantly-designed zipper that prevents the fabric from snagging.

Full Specifications

Available in different sizes and temperature ratings / comfort rating: -10ºC comfort limit: -18ºC / length: 73 inches, 80 inches or 85 inches / fill: 650 fill power RDS duck down with Nikwax hydrophobic treatment / shell” 20D Polyester / liner: 20D Polyester Taffeta.

Check out our full Therm-a-rest Questar 0F/-18C review.

Buy the Therm-a-rest Quester 0F: £249 at Wildbounds.com

2. Kelty Cosmic Down 20 Bag

Our top pick if you’re looking for value

On the right, the Cosmic Down 20 in use during one of our test trips

Price: £130
Weight: 1.19kg
Key attributes: Excellent value, responsibly-sourced down and PFC-free fabrics
Temperature rating: comfort rating: 0C / comfort limit: -6C
Fill type: down

We really like this sleeping bag here at Outdoors Magic. Using it, you wouldn’t think it’s a sub £200 bag as it has the comfort, loftiness and light weight design of a much more expensive model. OK, the down fill isn’t the most thermally efficient (it’s rated at 550 fill power) but it still brings enough warmth for general three-season use. It might just get tested on any very cold nights at the start of spring or late on in autumn.

Unlike most low-cost rivals, its cosy down is exclusively sourced from Allied Feather + Down, which is an RDS (Responsible Down Standard) certified supplier. The bag’s shell fabrics additionally only use environmental and health-friendly PFC-free durable water repellent (DWR) treatments.

All in all, this is a great value bag with some decent eco credentials.

Full Specifications

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 Greener Gear Guide – Here’s our full Kelty Cosmic Down Sleeping Bag review.

Buy the Kelty Comsic Down 20: £135 at Wildbounds.com

3. NEMO Forte 20

Best for the eco-conscious camper

Price: £220
Weight: 1600g
Key attributes: unique design details, excellent sustainability credentials
Temperature rating: comfort rating: 7C / comfort limit: -6C
Length: 202cm
Fill type: synthetic

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 and the result, we found, made for a sleeping bag that felt voluminous, with loads of wiggle room.

It’s available in men’s and women’s versions, 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. We found that it was a little chilly when temperatures got below freezing and, as such, some early spring and late autumn nights will stretch this bag. For general three-season use, however, it’s ideal and certainly a good choice for anyone who is conscious of their eco footprint.

Full Specifications

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.

Buy the Nemo Forte 20: £220 at Ellis-brigham.co.uk

4. Snugpak Softie 6

Best if you want the wet weather performance of a synthetic sleeping bag

Price: £150
Weight: 1200g
Key attributes: warm when wet, durable, UK-made
Temperature rating: comfort rating: 0, comfort limit: -5C
Fill type: synthetic

It’s hard to believe this sleeping bag isn’t filled with down because it’s so unbelievably lofty and snug and it’s packable and light too.

Snugpak isn’t that well-known a brand beyond the core outdoor scene in the UK, but they make some excellent products worthy of greater recognition. We’ve long been big fans of their Softie insulation here at Outdoors Magic. And that’s wherever it’s applied, be that in their jackets or in the sleeping bags. First developed in the 1980s, and much-loved by those in the military, it’s been refined more and more over the years and today you can expect it to provide excellent warmth to weight, even in wet conditions.

Snugpak make a bunch of Softie sleeping bags to suit a wide range of temperatures. This, the Softie 6, is probably the best for three-season versatility, offering a comfort rating of 0°C / 32°F and a limit of -5°C / 23°F.

Useful details include an elasticated drawcord hood, a two-way anti-snag zip (useful for night time ventilation), inner baffles to block out draughts and there are compression straps on the stuff sack. One final nice touch is that there’s potential to sync this with another Snugpak sleeping bag to create a big shareable bag.

Again, from our experience using this it is another sleeping bag that can be stretched on very cold nights during early spring and late autumn. If you want something for very chilly nights, it’s worth looking at the Snugpak Softie 9 or 10 models.

Full Specifications

Available in standard and extra long lengths / Face fabric: 100% nylon / Inner fabric: 100% nylon / Fill: 100% polyester / two-way YKK zip / Packsize: 19cm x 18cm / 7″ x 7″ / Temperature Rating Comfort: 0°C / 32°F / Temperature Rating Low: -5°C / 23°F.

Buy the Snugpak Softie 6: £155 at Alpinetrek.co.uk

5. Montbell Seamless Down Hugger

Our top pick if you’re looking for something that’s light enough for ultralight hiking and fastpacking

On the right, Will with the Montbell Seamless Down Hugger during a fastpacking campout.

Price: From €359
Weight: 541g
Key attributes: Exceptionally lightweight, totally windproof
Temperature rating: comfort rating: 4C, comfort limit: -1C
Length: 170cm
Fill type: down

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. We’ve used this extensively on numerous fastpacking trips and consider it a go-to option if you want something warm but lightweight.

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. It seems to work well.

On top of all that (quite literally), Montbell has used Gore’s 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℃ and, from our experience, this 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. One final thing to bear in mind is that this sleeping bag isn’t great for tall people (length is 170cm) It was fine for our 5 foot 10 tester though.

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 review.

Buy the Montbell Seamless Down Huger: £225 at Ultralightoutdoorgear.co.uk

6. Rab Alpine 800

Price: £330
Weight: 1260g
Key attributes: Good warmth-to-weight, lofty fill
Temperature rating: comfort limit: -16C
Length: 215 or 230cm
Fill type: down

During our tests with this sleeping bag we were impressed by the loftiness of its 650 fill power fill and the cosy warmth inside it. We used it on a frosty trip in the Cairngorms and it was a reliably comfortable cocoon.

Rab have used some quality materials and ingredients here, including European down that’s treated with Nikwax, a durable but lightweight Pertex Quantum outer shell fabric that’s made from 100% recycled materials and, finally, YKK zips.

The main two-way zip was handy for regulating the temperature inside the bag and the zipped pocket at the hood was useful for keeping a head torch or your phone close at hand. The only downside to this sleeping bag is its stuff sack which is a little on the basic side with no compression straps to let you really reduce the packed size.

Full Specifications

Available in different sizes and temperature ratings / sleep limit: -16C / Lengths: 85 inches or 90 inch / fill: 800g 650 fill power European duck down / Nikwax hydrophobic treatment / shell: 20D Pertex Quantum / liner: 20D recycled nylon.

Check out our full Rab Alpine Pro 600 review.

Buy the Rab Alpine 800: £330 at Rab.equipment

Forclaz MT500 -5C

Griff, the editor’s dog in the Forclaz MT500 during our tests.

Price: £90
Weight: 1650g
Key attributes: Good value, useful details, can stretch into winter
Temperature rating: -5C comfort rating, -11C limit
Length: 185cm (Large)
Fill type: Synthetic

While this might be classed as a three-season sleeping bag, it’s very warm for the category. In fact, we’ve found it to be warm enough for a lot of UK winter nights – at least those that don’t drop below -5C. As such, we’d say this is a three-season sleeping bag with enough insulation to keep you warm at the shoulders of spring and autumn and on the more forgiving winter nights. In our tests, we found this had a lot of the features we look for from a sleeping bag, including an internal draught baffle, zippers that are easy to locate and that glide nicely, a phone or head torch pocket and a two-way zip that lets you open up the bag at the legs when you want a bit of ventilation.

The synthetic fill isn’t particularly lofty and light feeling and it instead feels thick and flat. It still brings a good deal of warmth without cold spots though, and we felt confident that it could resist any moisture from condensation in our tent.

At 1650g, it’s quite a heavy sleeping bag and, while you can easily compress it down to fit into the base of a backpack, it is on the cumbersome side. Still, what you get is pretty good for the price. There are certainly warmer and lighter three-to-four season bags out there, but they will cost a heck of a lot more than £90.

Full Specifications

Available in M, L and XL / Face fabric: polyester / lining: polyester / insulation: synthetic (polyester) / comfort rating: -5C / limit rating: -11C / pack size: 16L.

Buy the Forclaz MT500: £90 at Decathlon.co.uk

7. Rab Neutrino Pro 400

Price: £420
Weight: 775g
Key attributes: High quality design, 800 fill power, durable face fabric
Temperature rating: comfort rating: -1ºC, comfort limit: -7ºC
Length: 160cm to 190cm
Fill type: down

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.

Buy the Rab Neutrino Pro 400: £420 at Ellis-brigham.co.uk

8. Mountain Equipment Firelite

Price: £510
Weight: 770g
Key attributes: 800 fill power, impressive warmth-to-weight, good features
Temperature rating: comfort rating: -2ºC comfort limit: -8C
Length: 185cm
Fill type: down

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.

Buy the Mountain Equipment Firelite: £510 at Alpinetrek.co.uk

9. Gruezi Biopod DownWool Ice 185

Jordan Tiernan in the Gruezi. It was chosen for our Outdoor 100 2020

Price: £369
Weight: 1400g
Key attributes: Innovative technology, effective in damp conditions
Temperature rating: comfort rating: 2C, comfort limit: -4C
Length: 176 to 190cm
Fill type: down and wool

Uniquely 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.

OK, it’s not the lightest sleeping bag out there but it’s still worth considering due to the unique cosiness, warmth and moisture resistance that the wool content provides.

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.

Buy the Gruezi Biopod Downwool Ice 185: £399 at Alpinetrek.co.uk

10. Nemo Disco Endless Promise 15F

The Nemo Disco pictured during our Lake District test trip.

Price: £320
Weight: 1257g
Key attributes: very lofty and snug, excellent eco credentials
Temperature rating: comfort: -3C, limit: -9C
Length: 183cm and 198cm
Fill type: down

This is a luxuriously lofty down sleeping bag that makes for a very comfortable night’s sleep in temperatures as low as -3C. It also has some excellent eco credentials, because, like the Nemo Forte which is also in this list, it is designed for circularity, with repairability and recyclability all factored into the design thinking and recycled materials already used.

This is also a sleeping bag that’s specially designed for side sleepers, with extra room at the knees and at the elbows while narrowing at the feet and lower torso. This gives wiggle room where it’s needed while also ensuring that the overall weight is still light – 1.3kg to be precise.

You can also expect little zipped vents at the torso that can be opened up when you want to dump heat and they’re covered by a very thin layer of fabric that lets warm air escape will keeping out draughts. A two-way zip also gives a venting option down at the base of the sleeping bag.

Full Specifications

Fill Power: 650 / hydrophobic treated / 30D nylon ripstop fabric / traceable responsibly sourced down / Comfort: 27°F | -3°C / Limit: 16°F | -9°C.

Read our full Nemo Disco 15 review.

Buy the Nemo Disco 15: £320 at Ellis-brigham.co.uk

What Makes a Good Three-Season Sleeping Bag?

At the most basic level, the best three-season sleeping bag is one that will give you a good night’s sleep. But, when it comes to outdoor adventure, the reality is that you actually need a sleeping bag that has a bit more to it. If you’re a backpacker, for instance, you’re going to want a sleeping bag that is light and packable, so that it’ll make your life easier in the day as well as in the night. Then there are other considerations, including your budget and your environmental conscience. One of the main questions to start with is whether you want a down filled sleeping bag or a synthetic filled one.

Down Versus Synthetic

We wouldn’t really call the down versus synthetic thing an argument, as some people do. It’s more to do with personal preferences and scenarios.

For its weight, down is the warmest, lightest and most packable option. Its main disadvantage, however, is that if it gets wet, it loses its insulating properties. Synthetic sleeping bags are generally heavier and bulkier but they also tend to be cheaper and they will provide insulation even in wet conditions.

Generally speaking, down tends to be favoured by ultralight hikers and backpackers, while synthetic filled sleeping bags are favoured by those who aren’t too concerned by their pack weight or that want reliable warmth in wet conditions. Still, it’s fair to say that the performance gap between down and synthetic insulation is narrowing, so you can now find down sleeping bags that are treated to withstand wet weather and synthetic filled bags that have impressive warmth-to-weight ratios.

The Different Sleeping Bag Constructions

Sleeping bags come in two primary designs: Rectangular and Mummy, with the latter being by far the most popular design today.

Rectangular sleeping bags offer ample space for movement and versatility, often doubling as quilts or blankets when unzipped. They are more budget-friendly but tend to be heavier and bulkier and their designs usually make them less suitable for cold weather due to potential heat loss. Mummy sleeping bags, on the other hand, prioritise thermal efficiency and weight reduction. They have a snug fit that reduces dead air space, enhancing warmth retention, and they tend to pack down smaller, making them ideal for backpacking and colder conditions. Their downside is that some people, especially those who move about in their sleep, find them restrictive.

Baffle Design

Within sleeping bag designs, the baffle design has a big impact on the overall performance. Sewn-through baffles tend to be seen on lower cost sleeping bags as the design is less technical and, with these types of bags, thermal efficiency doesn’t tend to be great. Often you can find they allow for cold spots along seams due to heat loss, compromising warmth.

Box baffles, alternatively, prevent insulation from shifting, ensuring consistent warmth throughout the bag. This type of baffling is found on all of the leading sleeping bag designs.

Patagonia’s example of a sleeping bag with vertical baffles

Then there’s the orientation of the baffles with the choice between vertical and horizontal. Look online and you’ll find generally inconclusive arguments about the advantages and disadvantages of these different types when weighed against each other. Some say that vertical baffles limit the movement of insulation, ensuring that it stays evenly distributed throughout the bag while horizontal baffles allow the insulation to be shifted within the bag, offering more flexibility to adjust warmth according to personal preference. These days, just about all sleeping bags have horizontal baffles and that should perhaps say enough about which kind is best!

Sleeping Bag Temperature Ratings Explained

To compare the warmth of different bags, look at their temperature ratings. Many sleeping bag brands use a rating – normally by the European Norm (EN) standard or the ISO (International Organisation of Standardisation).

The EN standard is represented by three temperature ratings – comfort, limit, and extreme. 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 ISO standard focuses on a single rating, the lower limit, indicating the lowest temperature at which an average adult male can have a restful sleep.

A three-season sleeping bag typically has a temperature rating between 10°F to 32°F (-12°C to 0°C). This rating is designed to provide comfort and warmth during spring, summer, and fall, covering a range of moderate to slightly chilly conditions. The figure you need to consider most, we’d say, is the limit rating. Most of the bags featured here have a limit rating of around -5ºC.

Other Things to Consider

Many sleeping bags come in different lengths so it’s worth just checking that you’ve got the right size for you when you buy. Don’t be tempted to go for a longer bag than you need as you’ll have to work harder to warm up the empty space in the bag.

There’s also the ethical side of things. We all have different levels of conscientiousness here but, to put it simply, if you care about your eco footprint, look for high amount of recycled and recyclable content and, if you’re buying a down filled bag, look for RDS down. RDS, or Responsible Down Standard certification guarantees that the that’s down used comes from ducks or geese that have been treated humanely, without unnecessary harm, including force-feeding or live-plucking. The certification also verifies traceability throughout the supply chain, ensuring that the down in the product can be traced back to RDS-certified farms.