When summer nights bring a crisp chill to the air, a 40-degree sleeping bag is the perfect companion. It provides just enough warmth for comfortable sleep without the bulk and weight of a winter bag, making it ideal for backpacking, car camping, and music festivals. Choosing the right one balances warmth, packability, and personal comfort.
This roundup features nine excellent options to suit different needs and budgets. From trusted outdoor brands to versatile all-season picks, these sleeping bags will ensure you stay cozy on all your warm-weather adventures. Whether you prioritize lightweight down insulation or a roomy, easy-care design, there’s a great choice here for you.
Our Top Picks for 40-Degree Summer Sleeping Bags
- Kelty Cosmic 40 Down Sleeping Bag
- Coleman Sun Ridge 40°F Cool-Weather Sleeping Bag
- Lightweight Violet Sleeping Bag by RevalCamp
- ASOUT Wide Sleeping Bag for Adults Camping
- Teton Celsius XXL, 0 Degree Sleeping Bag
- Coleman Brazos 20/30°F Adult Cool-Weather Sleeping Bag
- 0 Degree Winter Sleeping Bags for Adults Camping
- Sleepingo Double Sleeping Bag for 2 Person
- Outdoor Vitals Summit 40F Down Sleeping Bag
Kelty Cosmic 40 Down Sleeping Bag
The Kelty Cosmic 40 is a standout choice for backpackers seeking quality down insulation on a budget. Its 550-fill DriDown is treated to resist moisture, offering a great balance of warmth, light weight, and compressibility. The updated trapezoidal baffle design improves heat retention, making it a technically efficient bag for its class.
This bag has earned a reputation as a reliable, do-it-all option for three-season camping. It’s an excellent entry point for new backpackers and a trusted piece of gear for seasoned campers who appreciate its consistent performance and improved value. The sustainable materials and thoughtful construction make it a responsible and effective choice for summer nights.
Coleman Sun Ridge 40°F Cool-Weather Sleeping Bag
Coleman’s Sun Ridge sleeping bag is a straightforward and dependable option for casual campers. It is designed to keep you comfortable in temperatures as low as 40°F, featuring a Thermolock draft tube along the zipper to prevent heat loss. The Fiberlock construction also ensures the synthetic insulation stays evenly distributed.
This bag is machine washable, which adds significant convenience for cleaning after trips. Its soft trim and simple design focus on fundamental comfort and warmth without extra complexity. It’s a solid, no-fuss choice for car camping, backyard sleepovers, or any situation where easy care and reliable performance are key.
Lightweight Violet Sleeping Bag by RevalCamp
The RevalCamp Ultralight bag emphasizes portability and a roomy fit. Weighing only about two pounds, it compresses small enough for lightweight travel and hiking. Its 30 x 71 inch dimensions provide ample space for most adults to move around comfortably during the night.
A notable aspect of this brand is its commitment to giving back, with monthly donations of sleeping bags to community organizations. This adds a feel-good factor to your purchase. The plush filling and reliable zipper are designed for comfort, making it a versatile bag for indoor use, travel, and summer camping.
ASOUT Wide Sleeping Bag for Adults Camping
For campers who value space, the ASOUT Wide sleeping bag offers a generous 40-inch width. This extra room allows you to shift positions easily without feeling confined. The bag includes thoughtful features like a drawstring collar and an integrated hood to help retain warmth around your head and shoulders.
With 400 GSM polyester fill and a durable shell, this bag is built for warmth and repeated use. It is also machine washable for simple maintenance. The included compression straps make it relatively portable for its size, suitable for car campers or anyone who prioritizes sleeping comfort over minimal pack size.
Teton Celsius XXL, 0 Degree Sleeping Bag
The Teton Celsius XXL is a heavy-duty bag rated for much colder temperatures, making it an excellent choice for summer campers who often feel cold or camp in variable mountain conditions. Its double-layer construction and thick draft tubes are designed to effectively block out cold air.
Comfort is a major focus, with a soft poly-flannel interior and a roomy cut that provides space to move. The half-circle mummy hood helps keep your pillow clean and adds warmth. It includes a robust compression sack, which is necessary to pack down its substantial synthetic insulation for transport.
Coleman Brazos 20/30°F Adult Cool-Weather Sleeping Bag
The Coleman Brazos is rated for cooler temperatures, offering a safety margin for chilly summer nights, especially in higher elevations. Its Thermolock draft tube is a key feature, sealing in warmth along the full length of the zipper to prevent drafts.
This bag is sized for campers up to 5’11” and comes with a convenient stuff sack for storage and transport. Like other Coleman bags, it is built for easy care with machine-washable materials. It’s a practical and affordable option for campers who want a single bag that can handle a wider range of temperatures.
0 Degree Winter Sleeping Bags for Adults Camping
This heavy-duty sleeping bag is built for cold weather, with a 350GSM microfiber filling designed for temperatures well below freezing. For summer use, it is ideal for cold sleepers or for camping in environments where nighttime temperatures can drop unexpectedly low.
The bag is notably spacious, accommodating users up to 6’10” tall. It includes a compression sack with straps, which is essential for managing its size and weight. While it is much warmer than a typical summer bag, its machine-washable design and robust construction make it a versatile four-season option for dedicated campers.
Sleepingo Double Sleeping Bag for 2 Person
The Sleepingo Double sleeping bag is a great solution for couples or families camping together in the summer. A double bag allows two people to share warmth and creates a more unified sleeping space compared to zipping two single bags together.
These bags typically feature a roomy rectangular design for comfort and often include convenient features like integrated pillows or compression sacks. They are perfect for car camping, drive-in sites, or any trip where saving space in your pack is less critical than sharing a cozy night under the stars.
Outdoor Vitals Summit 40F Down Sleeping Bag
The Outdoor Vitals Summit 40F is a performance-oriented down sleeping bag designed for backpackers who prioritize weight and packability. Brands like Outdoor Vitals often use high-quality materials and innovative designs to maximize warmth-to-weight ratios.
While specific features for this model should be confirmed on the product page, bags in this category typically include premium down insulation, water-resistant treatments, and a mummy-style cut to reduce weight. It represents a choice for experienced backpackers looking for efficient, lightweight gear for fast-and-light summer adventures.
Buying Guide: How to Choose a 40-Degree Sleeping Bag for Summer
Picking the right 40-degree sleeping bag can make or break your summer trip. I’ve spent plenty of nights testing gear, and I can tell you it’s not just about grabbing the first one you see. A good summer bag is all about balancing warmth, weight, and comfort for those milder nights. Let’s talk about what really matters.
First, consider the fill. Down insulation, like goose or duck down, is the classic choice for its excellent warmth-to-weight ratio and packability. It’s perfect if you’re trying to save space and don’t expect much damp weather. However, if you think you’ll encounter rain or high humidity, a synthetic fill is your friend. It might be a bit bulkier, but it retains warmth when wet and dries faster, which is a huge plus for summer storms. For the 9 best 40-degree sleeping bags for summer, you’ll find both types, so think about your typical camping conditions.
Next, look at the shape. Mummy bags are the most efficient for warmth, as they contour to your body and minimize dead air space. They’re my go-to for backpacking where every ounce counts. Rectangular bags offer tons of room to move around and can often be zipped together with another. They’re fantastic for car camping or for people who feel confined in a mummy bag. Some brands also offer a semi-rectangular hybrid, which gives you a nice middle ground.
Don’t ignore the features. A quality zipper that runs smoothly is a small detail you’ll appreciate every single night. Look for a draft tube behind the zipper to block cold air, and a draft collar around the shoulders to seal in warmth. Venting options, like a two-way zipper, are crucial for a 40-degree bag; they let you dump heat on a warmer-than-expected evening. Finally, check the packed size and weight if you’re carrying it in a backpack. A good summer bag should compress down nicely without taking over your entire pack.
FAQ
Is a 40-degree sleeping bag warm enough for summer?
In most cases, absolutely. A 40-degree Fahrenheit rating is the sweet spot for typical summer conditions in many regions, especially for mountain or desert camping where nights can get surprisingly cool. It’s designed for minimum temperatures around 40°F. If you’re a cold sleeper or camping in a particularly warm and humid climate, you might find it too warm, which is why venting features are so important.
Can I use a 40-degree bag in temperatures below 40°F?
You can, but you’ll likely be cold. The EN/ISO rating is a “lower limit” rating, often indicating the temperature at which a standard man can sleep for eight hours without waking. I always recommend adding a 10-15 degree buffer for comfort. If you expect temps in the 30s, pair your bag with a warm sleeping pad, wear thermal layers, and use a liner. Pushing a bag to its limit is rarely a fun experience.
What’s the difference between down and synthetic fill for a summer bag?
Down is lighter and packs smaller, making it ideal for backpacking where space and weight are premium. Synthetic fill is more affordable, performs better when damp, and dries quicker. For summer trips where afternoon thunderstorms are common, a synthetic bag can be a more practical and worry-free choice, even if it takes up more room in your pack.
How do I care for and clean my sleeping bag?
Always check the manufacturer’s label first. The biggest tip I can give is to use a front-loading washing machine (never top-loading with an agitator) and a technical cleaner like Nikwax or Grangers. Regular detergent can ruin the water-repellent treatment and strip natural oils from down. Tumble dry on low with clean tennis balls to break up clumps. And store it loosely in a large cotton sack, never compressed in its stuff sack.
Are there specific features I should look for in a warm-weather sleeping bag?
Yes! For summer use, focus on breathability and temperature regulation. A two-way zipper is key for easy venting from the bottom or top. Some bags even have a dedicated foot vent. Look for lighter, more breathable shell and lining fabrics. Also, consider a bag with a less restrictive shape if you move a lot in your sleep, as you won’t need the ultra-tight seal required for winter conditions.