Last Updated on 27/08/2023
Choosing the Best Warm Weather Sleeping Bags For Backpacking
In this guide to warm weather sleeping bags, we review some of the lightest and most compact summer sleeping bags for backpacking and hiking. You will learn which sleeping bags provide the perfect temperature and how to judge a sleeping bag’s warmth before you test it.
When you’re camping or backpacking, you want to wake up fresh every morning—ready for the day’s adventures. This means it’s imperative that you get a good night’s sleep! But when you’re backpacking in countries with hot climates, it can be hard to sleep well if you’re sweaty, overheating, and uncomfortable.
For cold weather and winter sleeping bags, check out this guide
So to guarantee you get a great snooze in hot climes, you need a sleeping bag that isn’t going to overheat easily. If you’re unsure which to choose, check out our guide to choosing the best warm-weather sleeping bags for hot climates at the bottom of the page.
Whether you plan on mainly sleeping in backpacking hostels or are taking a tent/hammock to camp wherever possible, then a sleeping pad is almost as important as your sleeping bag. Check out our guide to sleeping pads here!
Top 10 Best Warm Weather Sleeping Bags
Sea To Summit Spark Sp I Sleeping Bag
- WEIGHT: lbs oz / 360 g
- TEMPERATURE: 46° F / 8° c
- PACK SIZE: 1.55 liters
- MATERIALS: ULTRA-DRY Down 850+ FP European Goose Down insulation, 10D Pertex Quantum shell
The Sea To Summit Spark Sp I is a super lightweight sleeping bag for hot climates that compresses down so small you would not even believe it is a sleeping bag. About as minimal as it gets, the Spark Sp I is so packable that it can be used as a sleeping bag liner on winter expeditions.
The ULTRA-DRY Down and Pertex shell help to repel moisture and keep you warm on damp nights in the tent. If you are looking for the lightest option, then the Spark Sp I is possibly the best warm weather sleeping bag for you.
Marmot Atom Sleeping Bag
- WEIGHT: 1 lbs 5 oz / 590 g
- TEMPERATURE: 40° F / 4° c
- PACK SIZE: 3.6 litres
- MATERIALS: Certified 800+ Fill Power Goose Down insulation, Pertex Microlight 20d 100% Nylon Ripstop DWR shell
The Marmot Atom is another ultra-lightweight sleeping bag that excels in warmer conditions and packs down incredibly small. The silky smooth lining never feels clammy, and the fold-down second zipper increases ventilation on hot nights.
The sewn-thru curved baffle helps to keep the down from shifting, while the hood and foot box are both designed to minimize heat loss. The Down Defender improves water resistance on the inside, while the Pertex shell does a good job of deflecting moisture on the outside. One of the best sleeping bags for warm-weather backpacking as well as summer expeditions.
Thermarest Corus HD Quilt
- WEIGHT: 1 lb 6 oz / 640 g
- TEMPERATURE: 35° F / 2° c
- PACK SIZE: 10″ x 7″ / 25 cm x 17 cm
- MATERIALS: 650-fill Nikwax Hydrophobic Down insulation, 20D RipStop Polyester DWR shell, 20D Polyester Taffeta lining
The Thermarest Corus HD Quilt is not quite a sleeping bag, but it does have a foot box and sleeping pad attachment. A large baffle runs around the entire quilt to lock in heat and prevent any unwanted drafts, which can also be tucked underneath for the sleeping bag effect.
Ventilation is not an issue with this design, allowing you to stick your feet out of the end if you wish or cocoon up in the foot box. The Nikwax Hydrophobic Down has been treated to repel water and dry out very fast to dispel all the myths about being useless when wet. The Corus HD quilt is incredibly versatile and great for lightweight backpacking or even keeping in the car for emergencies.
Western Mountaineering Mitylite Sleeping Bag
- WEIGHT: 1 lbs 10 oz / 735 g
- TEMPERATURE: 40° F / 4° c
- PACK SIZE: 6″ x 12″ / 15 cm x 30 cm
- MATERIALS: 12 oz Down insulation, 0.9-ounce ripstop shell
The Western Mountaineering Mitylite is a semi-rectangular summer sleeping bag with a sewn thru construction and horizontal chambers. Because of its rectangular shape, it can be zipped to other sleeping bags to make a double or unzipped completely to use as a quilt.
The 6-inch continuous chambers have a 3-inch loft which helps to retain body heat on cold nights and packs down nice and small. Made in the USA, the Mitylite is suitable for lightweight backpacking trips where the temperature rarely drops below 0° C or when you intend to stay in hostels/couch surf.
Mountain Hardwear Down Flip 35/50F Sleeping Bag
- WEIGHT: 1 lb 12 oz / 788 g
- TEMPERATURE: 35/50° F (1/10° c)
- PACK SIZE: 7″ x 14″ / 18 cm x 36 cm
- MATERIALS: Q.Shield Down 600-fill insulation, 30D Nylon Plain Weave shell, 30D Nylon Plain Weave lining
The Mountain Hardwear Down Flip 35/50F is a semi-rectangular sleeping bag with more insulation on one side allowing you to flip it to suit the temperature. The Q.Shield Down is treated to resist moisture and maintain maximum loft to keep you warm in damp conditions.
The wide cut of the bag gives you plenty of space to stretch out at night as well as open it up to use as a double duvet in the back of the van. With great ventilation, this is a top sleeping bag for warm countries, backpacking hostels, road trips, and van life.
Sierra Designs DriDown Backcountry Bed 600 Sleeping Bag
- WEIGHT: 2 lbs 8 oz / 1,130 g
- TEMPERATURE: 27° F / -3° c
- PACK SIZE: 7.5″ x 15″ / 19 cm x 38 cm
- MATERIALS: 600 Fill Duck DriDown insulation, 30D Polyester Ripstop shell, 30D Polyester Taffeta lining
The Sierra Designs DriDown Backcountry Bed 600 Sleeping Bag has a versatile integrated comforter that allows you to stay wrapped up and open the top for ventilation at the same time.
The Sierra Designs sleeping bags really are as comfy as they look and allow lots of upper body space to sleep on your back, side, or front – or rotate between all three on restless nights! You can go even lighter with the 2-season version of this bag but are then more limited with the places you can comfortably use it. A really cool 3-season sleeping bag for unpredictable warm weather.
NEMO Salsa Sleeping Bag
- WEIGHT: 2 lbs 1 oz / 940 g
- TEMPERATURE: 30 F / -1 c
- PACK SIZE: 16″ x 8.5″ / 41 cm x 22 cm
- MATERIALS: 650 Fill Power Down with Downtek insulation, 30D Nylon Ripstop with DWR shell, 30D Nylon Ripstop with DWR foot box, 30D Nylon Taffeta with DWR lining
The NEMO Salsa is a 3-season spoon-shaped sleeping bag designed for backpacking in warmer climates. The shape is a kind of mummy/rectangular hybrid that adds extra room for your knees and elbows if you are a side sleeper.
With a stretch construction and stitching, this is a comfortable bag not just to sleep in but to lounge around in as well. NEMO‘s 650 FP down is super light and will keep you warm on chilly nights as well as regulate your heat on warmer nights. Other features include an adjustable hood, pillow slot, and zippered valuables pocket.
Big Agnes Cross Mountain 45 Sleeping Bag
- WEIGHT: 1 lb 10 oz / 737 g
- TEMPERATURE: 45° F / 7° c
- PACK SIZE: 7.5″ x 6″ / 19 cm x 15 cm
- MATERIALS: Hotstream by Insotect – 100% recycled polyester insulation, Nylon rip-stop shell with DWR, Nylon taffeta lining
The Big Agnes Cross Mountain 45 sleeping bag is designed to hold any 20-inch rectangular sleeping pad in the sleeve at the bottom. This means that you don’t roll off your bed in the night and adds to a better night’s sleep overall.
The synthetic insulation is very light and soft with properties very similar to feather down, and it packs down very small for a synthetic bag. The main benefits of this synthetic sleeping bag are that it can be used in all conditions and has more space than a mummy bag. This bag would be ideal for hot, humid, wet places like rainforests where keeping all your gear dry is near impossible.
Marmot Nanowave Sleeping Bag
- WEIGHT: 1 lb 13 oz / 822 g
- TEMPERATURE: 45° F / 7° c
- PACK SIZE: 5 Litres
- MATERIALS: Synthetic Spirafil High Loft insulation, 50d Polyester shell with DWR, 50d Polyester lining
The Marmot Nanowave Sleeping Bag uses high-loft synthetic insulation and so will keep you warm even when wet. The best thing about this sleeping bag, though, is the price.
The Nanowave is great value for money, so if you already have a high-end winter bag, then you don’t need to spend a lot of money to equip yourself for warmer climates. The only issue with this bag is that it doesn’t pack down as small as other bags on this list, but other than that, you can go wrong.
North Face Aleutian 55 F Sleeping Bag
- WEIGHT: 1 lb 11 oz / 762 g
- TEMPERATURE: 55° F / 13° c
- PACK SIZE: 7″ x 11″ / 18 cm x 28 cm
- MATERIALS: Heatseeker Eco synthetic insulation
The North Face Aleutian 55 F Sleeping Bag is a cheap sleeping bag rated for hot countries and summer weather. As with other synthetic sleeping bags, it doesn’t pack down very small, but it will keep you warm even if it gets wet.
It has a full-length zipper on one side, which runs right around the foot box, enabling you to open it up like a blanket as well as a quarter-length zip on the other side for more sleeping options. A good value summer sleeping bag ideal for festivals and casual camping when the weather is nice.
Guide to The Best Warm-Weather Sleeping Bags
These are some of the specifications worth looking into when buying any kind of sleeping bag for hot weather and summer use.
The first—and most important—aspect to consider when buying a sleeping bag is the temperature rating. In 2005, the European Advisory developed a legal standard for sleeping bags across all manufacturers. These temperature ratings have also been adopted in other parts of the world and are displayed in terms of “comfort” levels.
The “comfort temperature” on a bag is the minimum possible temperature that the sleeping bag is designed to withstand before the average human gets cold. These ratings range from a human’s “lower comfort level” to “upper comfort level” and “extreme” ratings (for the coldest temperatures).
Temperature ratings should be used as a guide to match your sleeping bag with the climate you are going to, but it is by no means 100% accurate. Just don’t buy a sleeping bag that’s designed for -10° C conditions, and you should be able to manage in most places.
So what is a good temperature rating for a summer sleeping bag? You should be looking for sleeping bags with a comfort rating of 40° F and higher, depending on the climate. Research the climate you are visiting and check the weather forecasts and then make an educated call on what temperature rating you want. It is ok to go a little cooler if you want to make use of the zips for breathability.
To make it simpler, sleeping bags also come with season ratings. The codes for ratings are:
- 1 Season Sleeping Bags: Summer (for use when the temperature is above 5 degrees).
- 2 Season Sleeping Bags: Spring/Summer (+0 degrees).
- 3 Season Sleeping Bags: Spring/Summer/Autumn (0 to -5 degrees).
- 4 Season Sleeping Bags: Year-round (-12 degrees and lower).
- 5 Season Sleeping Bags: Extremely cold conditions!
So if you’re heading to hot places, you’re best to buy a sleeping bag with a one or 2-season rating.
As with everything in life, some people can “take the heat” more than others. So when buying a sleeping bag, you need to consider your personal ability to cope with the heat. If you’re comfortable in warmer conditions, you should take this into account and possibly opt for a Season 2 bag. In general, women feel the cold more than men and have a lower body temperature at night than men, so they tend to need a slightly warmer sleeping bag.
A good rule of thumb is to buy a sleeping bag that is slightly warmer than you think you’ll need, as you can always take more clothes off and open ventilation zips.
When choosing any camping gear, one of the factors to consider is which material best suits your purpose. Most sleeping bags are filled with either synthetic fabric or down. When you’re traveling to hot places, synthetic-filled sleeping bags are a far better choice as they’re less insulating than down. They also retain 50% of their insulating capabilities when wet, which is ideal for damp and humid places.
Synthetic sleeping bags are also cheaper and need less care and cleaning than down sleeping bags, which makes them ideal for backpacking where you may be on a budget or traversing grubby environments. The downside of synthetic bags is that they can be bulkier and weigh more than down sleeping bags, so if you already have a heavy rucksack, this can be troublesome.
It’s also worth considering what the lining fabric is made of. In hot climates, avoid flannel linings due to their insulating capabilities. Opt for something light and breathable, such as cotton. If it’s extremely hot, but you still want some protection, you can buy a silk sleeping bag liner and use it instead of a sleeping bag, as silk keeps you incredibly cool.
Shape and Size Vs. Weight
Sleeping bags come in a range of shapes and sizes. The most common types are rectangular or “envelope” shaped sleeping bags and tapered or “mummy” shaped sleeping bags.
Mummy Sleeping bags for Summer
With a “mummy” sleeping bag, as you can imagine, the bag fits around your body as if you are mummified. Cheerful, right? The tapering of the bag means better heat retention, so this shape isn’t ideal for hot places. However, this type of bag weighs less than a rectangular bag. Mummy bags come with a “stuff” sack, topped with a drawstring and toggle, which enables them to be compressed dramatically. This makes it much easier to carry them when backpacking.
Rectangular Summer Sleeping Bags
With a rectangular bag, there is a zip around two sides, meaning the bag can be opened fully to form a blanket and gives you extra room to move around when zipped up. This is often better for warmer conditions, as it is less insulating and allows more airflow. However, rectangle bags weigh more than “mummy” bags, and they usually don’t come with a compression sack, so they can be bulky to carry, especially when backpacking.
Which to Choose?
When you’re deciding which shape sleeping bag to take backpacking in hot climates, it’s often better to buy a lightweight mummy bag that compresses small and has full-length zips so you can create ventilation if you get too warm—or find a lightweight rectangular bag with a stuff sack so it’s not too bulky to carry.
When it comes to sleeping bag zips, there are a few things to consider:
- Left or right-handed zips: To make it easier to hop out for a late-night call of nature, choose the right zip for you. Right-handed people need left-sided zips, and vice versa.
- Two-way zip: In warm conditions, it’s useful to have a two-way zip as you can create extra ventilation.
- Full-length or half-length: It’s also better to opt for a full-length zip in hot places, as you can open up your bag fully to let out the heat.
When backpacking, especially if you’re staying in hostels, it’s a good idea to look for a bag with inner pockets, usually placed near the top of the sleeping bag. This way, you can keep your valuable items close to you, such as your mobile phone or wallet. Hood closures are good for really cocooning yourself inside, which also prevents any creepy crawlies from getting into your sleeping bag while you sleep.
Sleeping bag liners are a great addition to summer sleeping bags as they can add a few degrees of warmth if the temperatures do drop, and they help to keep your sleeping bag dry. If you are using a down sleeping bag, then this is especially useful as you should avoid washing it down for as long as possible to keep its loft.
On a thru-hike or backpacking trip, showers aren’t always a given, and so you often end up going to bed dirty from the day’s adventures. It is so much easier to clean a sleeping bag liner than it is a sleeping bag, and they are super comfy too.
Frequently Asked Questions About Lightweight Sleeping Bags
Here are some of the common questions about warm-weather sleeping bags we have answered in the past:
What Is a Summer Sleeping Bag?
Summer sleeping bags are designed to be used in warm weather and so are not as insulative as cold-weather sleeping bags. They are the most lightweight of all seasonal sleeping bags and pack down incredibly small due to the lack of lofty insulation.
What Is the Best Type of Sleeping Bag for Summer?
The best warm weather sleeping bags should have both a season rating of between 1 – 2 and also have a comfort temperature rating of 40+ degrees Fahrenheit. You can get down or synthetic fillings that perform in different ways but can both be used in summer.
What Is the Best Type of Sleeping Bag for Warm Weather?
The best types of sleeping bags for warm weather should have a full-length zip so you can open it up if you get too hot or stick your legs out at the bottom. Breathability is often overlooked when buying a sleeping bag but down offers the best thermoregulation properties compared with synthetic ones. Wool blankets also offer great breathability, and some people use them instead of sleeping bags.
Do You Need a Sleeping Bag in Summer?
In some places, you don’t even need a sleeping bag because it is so hot a night. In this type of situation, a sleeping bag liner is a great substitute and that still provides a very thin yet breathable layer of protection against bugs and cold breezes at night. Camping without a tent does come with its own set of challenges, but it feels amazing to sleep under the stars without needing a tent for shelter.
Is It Warmer in A Sleeping Bag with Fewer Clothes On?
If you wear clothes in your sleeping bag, you add an extra layer of warmth to your sleeping system. Taking layers off inside your sleeping bag is a great way to cool down if you overheat on a night. Some people report sweating more without any pajamas or base layers which can cool you down in the early hours of the morning. I normally sleep in my merino base layer bottoms with a fleece up top.
Is a 20-Degree Sleeping Bag Too Hot for Summer?
A 20-degree Fahrenheit sleeping bag will be too hot for summer use. If it has a full-length zip, you can open it up and lay it over you like a quilt, but you would be far better off using a lighter summer bag. A temperature rating of 40 degrees F and upwards is ideal for warm nights camping under the stars. Check out this guide to camping in 20-degree weather for more information.
How to Warm up In Your Sleeping Bag?
If you get cold in your sleeping bag, there are a few things you can do to warm up at night. The first and most obvious thing is to do some exercise inside your sleeping bag. You can air jog, wiggle your toes, or do some crunches to increase blood flow to your limbs. The second thing you can do, which is more practical if you aren’t camping solo, is to put on some extra layers of clothing or double on your sleeping bag. Base layers are a great idea, but fleece, jackets, and extra socks all make a big difference.
How to Cool Down in Your Sleeping Bag?
If you get too hot inside your sleeping bag, the best thing to do is to unzip the side and get some air. Once you have cooled off, you can then sleep with the zip open and your legs out of the side. You can even open it right up and use it as a duvet on top of you. Take any excess layers of clothing off and unzip your tent door if camping. Get as much air flowing as possible until you cool down.
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