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 2024

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.

Best Overall Three-Season Sleeping Bag

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

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

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. 

Best Value Three-Season Sleeping Bag

2. Kelty Cosmic Down 20 Bag

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

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

-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.

Best Sustainably-Made Sleeping Bag

3. NEMO Forte 20

Price: £220
Weight: 1600g
Best for: Car camping, 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 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.

Best Synthetic Three-Season Sleeping Bag

4. Snugpak Softie 6

Price: £150
Weight: 1200g
Best for: wet weather camps
Key attributes: warm when wet, durable, UK-made

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.