8 Best 4 Season Sleeping Bags In 2024 | All Season Sleeping Bags

Last Updated on 11/05/2024

In this guide to the best 4 season sleeping bag, we look at some of the warmest, most weatherproof, and adaptable options available this year. We compare down to synthetic insulation as well focus on the specific features that make a sleeping bag good for 4 season camping

The main feature to look for in a 4 season sleeping bag is its temperature range – both comfort ratings and extreme limits. Comfort ratings determine the temperature you will feel warm in and the extreme rating determines the temperature that your sleeping bag will keep you alive. It is far more important for a four-season sleeping bag to keep you warm in winter than to be comfortable in summer – you can always unzip it if you get too hot.

Some other things to take into account are the weatherproofing, type of insulation, weight, and pack size among other things. We have a full guide on what to look for and answer some common questions beneath our recommendations for those who want to learn more.

8 Best 4 Season Sleeping Bags

NEMO Sonic 0 Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 0° F / -18° C
• WEIGHT: 3 lbs 4 oz / 1,470 g
• PACK SIZE: 13.5 x 9.5 in / 34 x 24 cm
• MATERIALS: Shell: 100% Recycled Nylon, Lining: 100% Recycled Nylon, Insulation: 800 FP Hydrophobic Down

The new NEMO Sonic 0 Sleeping Bag has been updated in 2022 to feature a new baffle system and updated ventilation holes. The improvements they have made make this the best 4 season sleeping bag for year-round use because you have more ability to control temperatures. Where most 4 season sleeping bags are geared toward the colder months, this one can do them all.

NEMO calls the two slits on the front Thermo Gills which extend the temperature range of the sleeping bag into summer use. In summer you leave them open for ventilation along with the side zip and in winter you can seal them up or use them to control your temperature once you are warm enough. On both the foot box and the hood, there is extra waterproofing in case they touch the inside of the tent walls with condensation.

The new chevron baffle system is overstuffed with premium 800FP hydrophobic down which they claim prevents migration and clumping. The down is very water resistant and especially dense around the foot box, hood, and top side. There are also two bolstering tubes of down on either side of the main zip to make sure all your warmth can be trapped in.

SUMMARY: If we had to pick one 4 season sleeping bag to use all year round, the Sonic -0° F from NEMO is the one we would pick. It will keep you warm from -0°F and feel comfortable up to 40°F with the side zip done up and the front vents open. You can also get an even warmer version that is comfortable down to -20° F for more extreme winter weather.

Sea to Summit Ascent 0-Degree Down Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 0° F / -18° C
• WEIGHT: 2 lbs 14 oz / 1,315 g
• PACK SIZE: 8.2 liters
• MATERIALS: Shell: 20D Nylon, Lining: 20D Nylon, Insulation: 750+ FP UltaDry Goose Down

The Sea to Summit Ascent 0-Degree Down Sleeping Bag is my favorite 4 season sleeping bag for backpacking because of how adaptable it is to any situation. You can use this down below freezing with everything zipped up or use it in summer with all the zips open.

It is zip coupling compatible so that if you are traveling with a partner and they have a women’s right-handed zip Sea to Summit sleeping bag you can link them both together for snuggles. There is a second zip that runs halfway on the opposite side to the full-length zip so you can completely flip back the top down to your legs in summer. A third double zip on the foot box allows you to also let your feet breathe and it cleverly overlaps the main side zip so that no warm air can escape.

Includes a stuff sack, semi-rigid bag to store it lofted instead of compacted, and down certificate. This certificate is worth having a read of as it will tell you the exact fill power your down tested at which for the bag we tested was much higher than the 750 FP rating the down is given by Sea to Summit. The down is water resistant although the outer shell could have used a DWR treatment to really improve its versatility.

SUMMARY: The Sea to Summit Ascent 0-Degree Down Sleeping Bag is an excellent option for backpackers who don’t have the luxury of being able to switch between a winter and summer sleeping bag. You can get the bag in three different warmth ratings from 25° F to this one which is the coldest at a 0° F temperature rating. A seriously good sleeping bag for any season.

Mountain Hardwear Phantom GORE-TEX 0 Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 0° F / -18° C
• WEIGHT: 3 lbs 5 oz / 1,460 g
• PACK SIZE: 17 x 9.5 in / 43 x 24 cm
• MATERIALS: Shell: 30D Gore-Tex WINDSTOPPER 2 Layer, Liner: 20D Nylon Taffeta, Insulation: 850-Fill-Power Goose Down

The Mountain Hardwear Phantom GORE-TEX 0 Sleeping Bag is one of the best 4 season sleeping bags out there because of its warmth and waterproof protection. Every little detail is well thought out to ensure reliability in the coldest environments on earth. Things like the direction of the baffles in different places for ultimate warmth and the ergonomic shape of the foot box mean that there are no cold spots and as soon as you zip up, you start to feel the warmth.

The shell is made from 30D Gore-Tex WINDSTOPPER fabric that is as waterproof as you can get while retaining breathability. This prevents moisture from getting in but allows it to permeate through the membrane from the inside if you sweat at night. The wind-blocking fabric is amazing in a hammock which can sometimes get chilly with a cold breeze.

One thing we noticed is that it does have a slightly snug fit which helps it warm up faster but can feel slightly restrictive. Comfort-wise, it really is phenomenal and feels like you are being hugged by a cloud. The down is high loft 850-fill-power goose down but unfortunately isn’t hydrophobically treated.

SUMMARY: The Phantom GORE-TEX 0 Sleeping Bag from Mountain Hardwear is one of the warmest for serious camping trips where you are out in all kinds of weather. If you are hunkering down in your tent during a snow storm then you will be glad you have this sleeping bag. The beauty of this 4 season sleeping bag is its weight and pack size which makes it one of the best options out there.

Therm-a-Rest Questar Lightweight Down Mummy Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 0° F / -18° C
• WEIGHT: 2 lbs 11 oz / 1,210 g
• PACK SIZE: 8 x 10 in / 20 x 25 cm
• MATERIALS: Shell: 20D Polyester with DWR, Lining: 20D Polyester Taffeta, Insulation: 650 fill Nikwax Hydrophobic Down

The Therm-a-Rest Questar Sleeping Bag is one of the best for 4 season camping and will keep you warm down to 0° F. The 650 fill power goose down is treated with Nikwax to make it completely hydrophobic which allows it to dry up to 3 times faster and absorb 90% less moisture than untreated down. Combine this hydrophobic down with the water-resistant shell and you have an awesome 4 season bag that won’t be affected by tent condensation or dew settling at night.

The outer material has a DWR treatment on the face which helps repel any beads of water on the surface as well as lets the sleeping bag breathe without feeling like you are in a bivvy bag. The down is segmented into zones that provide more insulation where you need it most including a generous amount in the foot box which keeps your feet warm past freezing without wearing socks. One last (small) thing is that on the underside it has some straps that fit your winter sleeping pad through so that it always stays in position with the hood at the bottom.

SUMMARY: The Questar Sleeping Bag from Therm-a-Rest is one of the coziest sleeping bags we have tested and it warms up within seconds of getting in. It packs down incredibly small and weighs well under 3 pounds which makes it a great choice for backpackers in cold climates. You can get three sizes to suit your build and you won’t be disappointed.

Western Mountaineering Kodiak GWS Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 0° F / -18° C
• WEIGHT: 3 lbs 5 oz / 1,500 g
• PACK SIZE: 9 x 18 in / 23 x 46 cm
• MATERIALS: Shell: Gore Windstopper, Insulation: Goose Down

The Western Mountaineering Kodiak GWS Sleeping Bag is one of the warmest 4 season sleeping bags you can use in winter without stepping into the expedition-level sleeping bag category. It features a Gore Windstopper fabric shell which not only blocks the wind but also repels water and stops any down from escaping through the seams. The baffles are absolutely packed with 30 ounces of lightweight down but we couldn’t find any mention of whether the down is RDS certified or hydroponically treated.

There is no doubt at all that this is a serious piece of camping gear but you better sit down when you check the price. You can see that all the best materials have been used and experts have had their hands all over it. Designed specifically for 4 season camping in temperatures well below freezing. Where some sleeping bags claim they will be warm down to 0° F, they actually feel start to feel cold around 10° F – but not this one.

SUMMARY: The Kodiak GWS is an elite sleeping bag made by professionals at Western Mountaineering for outdoor professionals. You can get warmer sleeping bags if you are camping in Antarctica but for most places on earth, you will never need another sleeping bag again. The only issue is that it is so warm you probably won’t want to use it in summer.

Marmot Lithium 0F Degree Down Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 0° F / -18° C
• WEIGHT: 2 lbs 9 oz / 1,176 g
• PACK SIZE: 16 x 7.5 in / 41 x 19 cm
• MATERIALS: Pertex Microlight Shell and Lining, Insulation: 850+ Fill Power Goose Down with Hydrophobic Treatment

The Marmot Lithium 0F Degree Down Sleeping Bag is super warm and cozy once you are fully zipped in thanks to the lofty 850+ fill power down. It is warmer than the Marmot Helium which is featured in our guide to zero-degree sleeping bags but I would definitely want to use a thermal sleeping bag liner in temperatures below 10° F.

The regular-size bag fits me perfectly although if I were any taller than 6 feet 2 inches I would go for the longer size. This is mostly because of how the shoulder zips work to really seal you in. You don’t get any internal neck baffles but this zip design means that it doesn’t really matter. One more benefit of having a zip on either side is that you can still sleep with one or both arms out of the sleeping bag and do things like read a book or play on your phone unrestricted. 

The baffles have a slight chevron curve to them which helps to restrict down migration and there is extra down around the feet, torso, and hood. The outer shell is made from Pertex Microlight which is really good. It is soft, durable, wind and water-resistant, and super lightweight. Two things I wanted to mention are that the stuff sack is very tight and the treated down does have a slight smell to it when you first get the bag so hang it on a washing line to air out if you can. 

SUMMARY: The Marmot Lithium 0F Degree Down Sleeping Bag is brilliant for 4 season camping in 95% of countries on earth although it is too hot for summer. The down is extra warm and loft and you can feel it heat up as soon as you get in. Definitely a sleeping bag you would be happy to have inside a tent while it snows outside.

Snugpak Special Forces 2 Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 10° F / -12° C
• WEIGHT: 3 lbs 14 oz / 1,700 g
• PACK SIZE: 9 x 9 in / 23 x 23 cm
• MATERIALS: Paratex Steelplate Weatherproof Shell, Softie Premier Insulation

The Snugpak Special Forces 2 Sleeping Bag is one used by armies around the world but originated in the UK. It is the warmest part of a 3-part sleeping system that includes a much lighter summer sleeping bag and a bivvy bag. But you actually don’t even need the other two parts if you don’t want them. If you do get the softie 1 which goes inside the softie 2, you can expect a comfort rating of 5° F and an extreme limit of -4° F.

I have owned a softie sleeping bag for nearly 20 years now and it still keeps me warm. The insulation is incredible in that it will keep you almost as warm when it is soaking wet as it will when it is dry. It mimics down in that it packs down very small and is lightweight but lofts up to provide maximum insulation in winter.

As the name suggests, this sleeping bag is super soft and the liner is probably the best we have tested. The outer shell is made from Snugpak’s Paratex Steelplate fabric, which is breathable, water-repellent, and windproof so that you can sleep under a tarp without getting chilled by the wind. A long central zip means that in the warmer months of the year you can sleep with it open (if you don’t have the softie 1).

SUMMARY: The Special Forces 2 Sleeping Bag from Snugpak is super soft and warm as well as incredibly durable and reliable in all weather and season of the year. If you get the complete 3-piece set including the Softie 1 and Bivvi Bag then you can adapt your sleeping system to suit the season anywhere on earth. Highly recommended by military troops.

Hyke & Byke Eolus 0F Hiking & Backpacking Sleeping Bag

• SEASON RATING: 4 Season
• TEMPERATURE RATING: 0° F / -18° C
• WEIGHT: 3 lbs 8 oz / 1,587 g
• PACK SIZE: 11 x 8 in / 28 x 20 cm
• MATERIALS: Shell: 20 D ripstop nylon with DWR Coating, Lining: 20 D ripstop nylon, Insulation: 625 FP ClusterLoft

The Hyke & Byke Eolus 0 F Hiking & Backpacking Sleeping Bag is easily the best budget 4 season sleeping bag and has some pretty impressive ratings for a synthetic sleeping bag that only weighs 3.5 pounds. It doesn’t pack down as small as other sleeping bags that can be compressed smaller than the stuff sack size. But it is extremely warm and durable for camping in bad weather.

The ClusterLoft synthetic insulation is designed to imitate goose down and according to the Outdoor Industry Association it is “the closest synthetic insulation to natural down ever developed”. This is why it has such a strong warmth-to-weight ratio and another reason why this is a great choice. The difference between real down and ClusterLoft is that if it gets wet it won’t all clump together and stop keeping you warm.

Some places where you can notice the difference between this and a higher-end 4 season sleeping bag are the attention paid to the zips, neck baffles, and inner lining. But considering the price difference between this and all the others, we think it’s totally worth it if you are on a budget and looking for good value.

SUMMARY: The Hyke & Byke Eolus 0 F Hiking & Backpacking Sleeping Bag offers some of the best value for money out there. You can use this in the coldest temperatures and it feels just like down so you always stay comfortable. You would be shocked at how little difference there is between this and a $400 sleeping bag.

Guide to The Best Sleeping Bags for 4 Seasons

Here we explain how we tested and ranked all the 4 season sleeping bags.

The term “4 season” gets applied to lots of camping gear but does it really mean you can use it all year round? For sleeping bags at least it does not. 4 season sleeping bags are often only suitable for the coldest months of the year.

As well as warmth we had to consider lots of other features and specifications to determine which was ultimately the best for the most amount of people. Here are the features we think you should consider:

Warmth

Warmth is perhaps the most important feature of a 4 season sleeping bag because any sleeping bag will work in summer but in winter, it takes a lot to keep you warm when camping. All of the sleeping bags we recommend will keep you warm below zero degrees thanks to an abundance of insulation, and that is what you need in winter.

It is better to be safe than sorry and get a sleeping bag that is warmer than you think you will need by at least 5 degrees Fahrenheit. Comfort ratings and extreme ratings for sleeping bags are very different – look at the comfort level and not the extreme limit.

Weatherproofing

When camping in all seasons of the year you are going to experience all kinds of weather including heavy rain and high humidity. Any time there is moisture in the air during the day which settles on a night your sleeping bag will be at risk of absorbing condensation or coming into contact with rainwater.

Many four-season sleeping bags will have some kind of durable water-repellent (DWR) treatment, lining, or laminate on the outside to protect you from any moisture in the air or stray raindrops. This always helps to protect the insulation from getting wet and in turn helps you stay warmer and more comfortable. DWRs are more important for down sleeping bags than synthetic ones.

If you want down insulation then look for whether it has been hydroponically treated to resist moisture. This has a big impact on warmth when damp and dry time if wet.

Another nice feature that shows the thoughtfulness of weatherproofing is whether there are any reinforcements on the foot box and hood. Extra waterproofing helps keep you dry if you touch the ends of a tent with condensation and reinforced foot boxes allow you to hop around a bit without getting out of your sleeping bag.

Weight

When warmth becomes a priority for your sleeping bag, weight is often the biggest compromise you have to make. People who go car camping and rarely carry their camping gear very far will not be so concerned with the weight of their sleeping bag. But backpackers, hikers, and anyone who is carrying their gear for more than a short distance should always compare the weights of the different options.

Down is without a doubt the most lightweight insulation and you can get varying levels of fill power which will determine how much loft the down has. Synthetic sleeping bags are getting more and more lightweight all the time and are starting to get very close to the warmth-to-weight ratios of down.

I would consider any 4 season sleeping bag under 3 pounds to be very lightweight and if you can stay under 4 pounds then you will be about average.

Pack Size

Just like with pack weight, how small an all-season sleeping bag packs down to will be more important to some people than others. If you are carrying all your gear inside your backpack then space is of a premium and takes residence over things like durability and price.

Down is again by far the most compactable type of sleeping bag insulation for all seasons although it gets more expensive the higher the fill power. While you want a sleeping bag that packs down small, it also needs to be able to reloft very quickly which is where synthetic insulation can be better.

Always store your sleeping bag uncompressed when possible to retain its loft.

Comfort

Comfort is important because without it you won’t sleep as well. To be comfortable in the coldest seasons you need warmth as well as enough space but in the warmer months, comfort might mean being able to fully open the zips to keep cool. Comfort also relates to how soft the lining is, how wide it is on the shoulders or at the foot box, and other features that may only matter to a small number of people.

Ventilation

Ventilation is super important for a 4 season sleeping bag that you want to use all year round. Sleeping bags designed for the coldest months of the year will be too warm in summer unless you can open the zips in such a way that lets you regulate your temperature. This might mean sleeping with your sleeping bag completely open and unzipped on top.

Double-way zips are crucial for airing out your feet as well as your upper body. Some sleeping bags like the Nemo Sonic listed above have special vents specifically designed to expand the range of seasons that the sleeping bag will work in. Others like the Sea to Summit Ascent have a third zip so that you can let more air in/out.

Year-Round Comfort

As mentioned above, not all 4-seasons sleeping bags are suitable to be used all year round – notably in the warmest months of the year. If you want a sleeping bag that you can truly use in any kind of weather in any country then the Sea to Summit Ascent paired with a sleeping bag liner would probably be my pick.

Down Vs Synthetic Insulation for 4 Season Sleeping Bags

Given the choice between synthetic insulation and goose down for all-season sleeping bags, we would opt for down insulation which has a better warmth-to-weight ratio. Synthetic insulation has its advantages too but the warmer a sleeping bag is the more insulation it will have, and synthetic insulation is heavier and bulkier than down. Here are the benefits of both

Benefits of Down Sleeping Bags

• Lightweight
• Very Warm
• Compact

Down sleeping bags are generally more lightweight and packable than insulated sleeping bags. Down is one of the warmest natural insulators when dry and with it also being lightweight it has something called good warmth-to-weight ratios.

Benefits of Synthetic Sleeping Bags

• Durable
• Washable
• Performs When Wet
• Cheaper

Synthetic sleeping bags are cheaper and more durable that down ones which also means they are easier to wash and care for. Another big advantage of synthetic fill is that it retains most of its thermal properties even when wet which down struggles to do if not properly treated.

Do You Need a 4 season Sleeping Bag?

Unless you plan on camping in winter and in some of the harshest environments on the planet then you don’t really need a 4 season sleeping bag. You can get by in the colder months by using your regular sleeping bag combined with a liner and wearing warm clothes to sleep in. I often pinch my teenage son’s sleeping bag to put inside 3 season bag.

Camping enthusiasts who love getting out into nature no matter the season or weather maybe do need one. Anyone exploring places like the North Pole needs one. Most people just want one and rarely use them to their limits, and that’s fine too.

If you are a cold sleeper and need to feel reassured that your sleeping bag will keep you warm no matter what then maybe you should get one too.

What Temperature is a 4 Season Sleeping Bag?

There is no set temperature rating for 4 season sleeping bags but as a guide, they should have a comfort rating of at least 20° F to ensure you stay warm past freezing. Extreme temperature limits can sometimes be exaggerated so it is safer to look at the range where you will feel comfortable. All 4 season sleeping bags are suitable for winter but many of them will feel too hot in summer.

Can You Use a 4 Season Sleeping Bag in Summer?

Some of the warmest 4 season sleeping bags will be too hot to use in summer with the zip sealed. You can use 4 season sleeping bags in summer if you leave the zips undone or completely pull back the top half. Some of the best 4 season sleeping bags are adaptable enough to be used in the coldest and warmest months of the year using multiple zips and sometimes vents. Here is our guide to summer sleeping bags.

Are 4 Season Sleeping Bags Waterproof?

As a rule, no sleeping bags are waterproof. Ok fine, are 4 season sleeping bags water resistant? As a rule, not all sleeping bags for four-season use are water resistant however most are. One of our favorite outer shell materials is Gore Windstopper which is extremely weatherproof without losing any breathability.

Conversion From Celsius to Fahrenheit for Sleeping Bags

Here is a quick list of temperature conversions from Fahrenheit to Celsius for 4 season sleeping bags in case you needed to know:

• 30° F = -1° C
• 25° F = -3.8° C
• 20° F = -6.6° C
• 15° F = -9.4° C
• 10° F = -12.2° C
• 5° F = -15° C
• 0° F = -17.7° C
• -5° F = -20° C
• -10° F = -23.2° C
• -15° F = -26.1° C
• -20° F = -28.9° C

We hope you found this guide to the best 4 season sleeping bag useful, it took me four days to write! Please let me know if you think I missed anything or if you want to learn more.