Best Cold Weather Sleeping Bags 2023

Summer is over, but that doesn’t mean camping has to be, especially with the right kit, we’re looking at the best cold weather sleeping bags to help you extend the camping season, allowing you to enjoy a few crisp winter nights in relative comfort. A winter sleeping bag alone be enough – it needs to be paired with a high R-rated sleeping mat and a decent tent – but it does go a long way!

Main Image The Nitro 0° | Credit: Sierra Designs

Choosing a cold weather sleeping bag is a game of compromise between weight, price, and warmth so you need to figure out which is more important to you. The fill type also impacts all of these. Down fill is warm and light but can be expensive, while synthetic is heavier, not as warm but usually cheaper.

Across Britain, winter temperatures can vary hugely. A night out could range from -15 to +5 degrees Celsius. Having a cold weather sleeping bag that is warm enough for the coldest nights, while still having options to vent a bit for warmer nights is useful, but that is a big range, so base your choice on where and when you plan to use the bag.

It’s generally a good idea to look for basic features like main zip baffles (aka draft tubes) which help to prevent cold spots, and anti-snagging zips, which reduce the chances of wrestling with your zip after a comfort break at 3am! A descent outer shell and a water resistant footbox go a long way in helping to retain warmth and improve durability, too.

Additional features that can be nice to have are pillow pockets, blanket collars, or zips to allow more ventilation, which can all help increase the comfort and the chance of a better night’s sleep.

How we tested our Cold Weather sleeping bags

Tested by Kirsty Pallas

Kirsty is 154cm tall and size 8, and usually sleeps fairly warm. She’s usually a side or front sleeper, so looks for bags with room for knees and elbows. These sleeping bags were tested in the Scottish Highlands through last winter and this autumn season, in both cold and wet conditions.

Tested by James Roddie

James is 180cm tall and average width shoulders. He is a ‘cold-sleeper’ and has taken this into consideration. The sleeping bags were tested in a variety of conditions throughout winter, spring and autumn in a variety of locations in the Scottish Highlands.

Cold weather sleeping bags

Sea to Summit, Women’s Altitude II – $399 / £400 | Kirsty’s Best Buy
Nemo, Women’s Riff 15 – $399 | £399.99 | Kirsty’s Recommended
Big Agnes, Women’s Sidewinder SL 20 – $299.95 | £245 | Kirsty’s Recommended
Thermarest Parsec -18 – £459 | U.S Shipping charges | Kirsty’s Recommended
Sierra Designs Nitro 0° – £324.99 | U.S Shipping charges | James’ Best Buy
Rab Alpine 800 – $365 | £330 | James’ Recommended
Robens Gully 1200 – £209.99 | U.S Shipping charges
Nemo Disco 15 – $300 | £319.99

Sea to Summit, Women’s Altitude II – Kirsty’s Best Buy

Sea to Summit, Women’s Altitude II

More info: seatosummit.co.uk

The Sea to Summit down cold weather sleeping bag is a comfortable and well-designed option for winter and shoulder seasons. It has an ultra-dry treatment and baffles that prevent the down fill from dropping to the sides. The bag has numerous zips, allowing for flexibility in folding and opening. Two-way zips are fitted to each section, allowing for customisation.

The hood is generous and can be cinched tight, and draft tubes are present along all zips. The top zip can be cinched separately with a drawcord. An internal pocket is small for a smartphone. The bag is designed for women, with additional insulation around the footbox and a narrower shape compared to a unisex bag. It comes with a mesh storage cube and a water-resistant compression sack. Overall, this bag is suitable for both winter and shoulder seasons, with the option to open it up.

See Kirsty’s full Sea to Summit, Women’s Altitude II Sleeping bag review

Nemo, Women’s Riff 15 – Kirsty’s Recommended

NEMO - Women's Riff Womens 15 - Down sleeping bag

More info: www.nemoequipment.eu

The Riff is a cosy bag from Nemo, with a comfort rating of -9 degrees Celsius and a high fill power of hydrophobic down. It features a waterproof footbox shell and baffles for warmth, but lacks body mapped insulation. The zip is two-way and full length, with a ‘zipper plough’ to prevent fabric from getting caught. Thermogills are used for ventilation. The hood is large and comes with a built-in pillow pocket, drawcord, and extra filled flap. The draft tube covers the zip and has an external pocket for a phone.

The bag is advertised as a spoon shape, designed for comfortable side and front sleeping. It comes with a mesh storage sack and a compression bag for packing. The bag is a great choice with some nice features, but adds to its weight.

Read Kirsty’s full Nemo Women’s Riff 15 Review

Big Agnes, Women’s Sidewinder SL 20 – Recommended

Big Agnes, Women’s Sidewinder SL 20 Reviewens 15 - Down sleeping bag

More info: www.bigagnes.com

The Sidewinder is a side sleeping bag with a water repellent down and synthetic insulation in key areas like the hips and footbox. It has a lower fill power and is comfort rated to +1 degrees Celsius. The bag features horizontal baffles and a grid pattern next to the zip, keeping the down in place. The shell and lining are water repellent.

The two-way zip runs full length down the front, with an anti-snag zipper. The hood is a nice size and shape, allowing the head to be fully tucked in. The bag has a draft collar around the outside and a mesh pillow barn around the outside. The zip has draft tubes on each side to keep out drafts. An internal pocket is just about big enough for a phone.

The bag has a classic mummy shape, but the zip up the middle and shaped footbox make it move with you. It comes with a mesh storage bag and a stuff sack, but the stuff sack doesn’t have compression straps. The Sidewinder is a great bag for side sleepers who are not planning to be out on the coldest nights but still deals well with temperatures hovering around freezing…

Read Kirsty’s full Big Agnes, Women’s Sidewinder SL 20 Review

Thermarest Parsec -18 – Recommended

Thermarest Parsec -18 (1)

More info: www.thermarest.com

Thermarest’s Parsec is a lightweight, warm, and comfortable bag designed for winter camping. It features hydrophobic down in heat-mapped zones and an insulated foot pocket. The bag has a two-way zip, anti-snag main zip, and a large draft collar for added warmth. The hood is large and has a cinch-tight design, while the zip has a draft tube and an external pocket.

The bag is unisex, mummy-shaped, and has a wider cut at the shoulders for side or front sleeping. Removable straps on the back allow the bag to be attached to a sleeping mat, but only suitable for three inches thick or less mats. The bag comes with a cotton storage sack and a compression bag, which is slightly harder to pack than a wider but shorter shape.

The Parsec is suitable for camping but comes with a price tag. Overall, the Parsec is a great choice for those looking for warmth and lightness in their winter camping gear.

Sierra Designs Nitro 0° – James’ Best Buy

Sierra Designs Nitro 0°

More info: sierradesigns.com

This cold weather sleeping bag is a lightweight, 1.25kg option for winter backpacking in the UK. It features a thin 15d ripstop nylon, a half-length zip, and minimal features. The insulation is 800 fillpower, responsibly sourced hydrophobic down, which performs well in damp conditions.

The hood is warm and easily adjustable, and the bag is warm enough for cold-sleepers. The draft tube along the zip and a generous draft collar prevent cold air from leaking in. The self-sealing foot vent is innovative, creating a seal when lying in the bag. This feature extends the temperature range and provides easy ventilation without the need for zips.

The bag is well-suited for winter backpacking in the UK and offers great value. Overall, this sleeping bag is an impressive choice for winter backpacking.

Read James’ full Sierra Designs Nitro 0° review

Rab Alpine 800 – Recommended

More info: rab.equipment/uk

The Alpine 800 is a lightweight, well-designed cold weather sleeping bag with 650 fill-power down, Responsible Down Standard certified, and a Nikwax hydrophobic finish. It is wind-resistant and copes well with damp and windy conditions. The down is stored in trapezoidal baffle chambers, keeping it closer to the body. The tapered mummy shape provides a snug fit, maximising insulation.

An angled foot-box keeps feet warm and minimizes down compression. The bag has an anti-snag zip guard, zip ‘plow,’ thick draft collar, draft tube, and small internal pocket. The outer and lining materials feel soft and comfortable on the skin.

However, the bag sheds feathers more easily than other sleeping bags, raising concerns about longevity. Overall, the Alpine 800 is a well-rounded sleeping bag for its price and weight, but a higher down fill power rating is recommended for cold sleepers.

Read James’ full Rab Alpine 800 review

Robens Gully 1200

More info: robens.de/en-gb/

The Robens Gully 1200 is a 220cm long, affordable winter sleeping bag designed for taller campers. Its spacious mummy shape offers ample freedom of movement. The bag’s materials are durable 50D polyester taffeta for the lining, and its insulation is a hybrid of duck down/MicroThermo Ball synthetic mix on the top and MicroThermo Ball on the bottom.

This waterproof blend insulates the bottom half of the bag, footbox, and hood, making it waterproof and allowing the bag to loft rapidly after compression. The bag features a zipped cushion pocket, two large internal pockets for keeping electronics warm, and an adjustable draft collar. At 1.98kg, it is the heaviest bag in this test, but it is manageable for winter backpacking and is the least expensive option.

It is likely the most durable sleeping bag in the long term.

Read James’ full Robens Gully 1200 review

Nemo Disco 15

More info: nemoequipment.com

The Disco 15 sleeping bag is a spacious and comfortable option for side-sleepers, offering a’spoon’ shape with contouring for extra room around the knees and elbows. It features a waterproof footbox, hood, and two long zipped slits for ventilation, but the zippers are fiddly and prone to snagging.

The main zip includes a zip ‘plow’ to reduce snagging. The Blanket Fold is an unusual feature, acting as an external draft collar, but it requires regular adjustment. The bag has a comfort temperature rating of -4°C, but it may be too warm for some users. The bag is suitable for milder winter conditions, but is a 3.5 season bag for warm sleepers.

The main zip is fiddly and prone to snagging, and the Blanket Fold may be a’marmite’ feature.

Read James’ full Nemo Disco 15 Review

Features to look for in winter sleeping bags

Shape and size

Cold weather sleeping bags often come in a regular and long size, so choose appropriately for your height. A mummy shaped bag hugs your body, making the best use of the insulation. Spoon shaped bags are best for side-sleepers. Women’s bags are generally designed to be shorter and may have insulation in different places to men.

Weight

There is usually a compromise between weight, insulation and price. An ultralight bag will be easier to carry, but either less warm or more expensive, or both.

Fill

Down insulation is very warm, lightweight and compressible, but far less effective when wet. Look for hydrophobic down – this has been treated to improve its water resistance. The higher the down fillpower (FP) rating, the higher quality and warmer the down for its weight. Synthetic insulation is heavier and less durable, but cheaper, quicker to dry and still retains some insulation value when damp.

Shell

A shell material with a higher Denier rating will be more durable, but also heavier. The lightest materials may allow feathers to escape through the material more easily on down bags. For water resistance, look for bags with a water-resistant (DWR) treatment.

Baffles/draft tubes

A draft tube of insulation-filled material running the length of the main zip (inside) helps to prevent heat loss. A draft collar around your shoulders is also crucial in a winter sleeping bag.

Zips and ventilation

These are usually 3/4 length. Shorter zips save weight. Two-way zips allow ventilation. Some bags offer features such as footbox vents.

Temperature ratings

Standard ISO ratings allow you to compare temperature ratings. ‘Comfort rating’ is the temperature at which a ‘standard woman’ is ‘not feeling cold’. ‘Limit rating’ is the temperature at which a ‘standard man’, curled up, resists hypothermia. Comfort in different temperatures varies widely between individuals and will depend on the effectiveness of your overall sleeping system.

Ethics

Down bags contain duck/goose products. Look for RDS certification for cruelty-free down. Synthetic bags can be made from recycled products but have a shorter lifespan, and microfibres can cause environmental issues.

The best cold weather sleeping bags 2024

Mountain Instructor Kirsty Pallas and wildlife photographer James Roddie keep the cold at bay with the very best in sleeping bags designed for winter.