As the weather gets warmer, it’s time to swap out your heavy winter sleeping bag for a lighter one made specifically for summer trips.
But with lots of choices out there, how do you pick the perfect bag for your next adventure?
In this guide, we’ll talk about the 5 best ultralight and lightweight sleeping bags made for warm weather.
Whether you’re a serious backpacker trying to cut down on weight or just a casual camper, focus on the weight and temperature rating when making your decision.
Let’s get started.
Key Specs
Weight: 13.5 ounces (383 grams)
Limit Temp Rating: 36ºF | 2ºC
Price: $$$
PROS
✅ Ultralight
✅ Functional temperature rating
CONS
❌ Even distribution of down needs some effort
The FlyLite defines ultralight backpacking sleeping bags. At a mere 13.5 ounces, it is the lightest fully baffled bag on the market. Western Mountaineering achieves this feat through micro baffles that eliminate cold spots while retaining enough loft for insulation.
Built from lightweight 10D nylon with an insulated half-length zipper and collar, the FlyLite compresses smaller than a water bottle. It is perfectly suited for fast and light adventures like lengthy thru-hikes where base weight is key.
After extensive testing, the FlyLite lives up to a 36°F comfort rating. Its form-fitting shape retains heat without bulk. Zipper draft tube and collar sealing keep cold out. No other bag offers this versatile balance of warmth, compressibility, and craftsmanship at such weight.
Wester Whether shaving ounces from a base weight or seeking reliable performance, this bag offers unparalleled value to ultralight adventurers.
Key Specs
Weight: 18.2 ounces (516 grams)
Limit Temp Rating: 35ºF | 1ºC* (Rated by Rab)
Price: $$$
PROS
✅ Lightweight
✅ Hydrophobic down
CONS
❌ None
The Rab Mythic 200 defines ultralight backpacking for two and three season adventures. Its tapered cut and 900 fill power goose down deliver warm, compressible performance.
Constructed from Rab’s durable and breathable Atmos recycled nylon fabric, the Mythic 200 manages a mere 18.2 ounces 516 grams on the scale. This low weight comes without compromise, as fully-baffled construction maintains down loft and wrap-around insulation.
A narrow mummy shape retains heat while minimizing pack size. Clever baffle placement along the zipper and collar prevent cold spots.
As a high-performance bag, the Mythic 200 excels for alpine starts, multi-pitch missions, or lengthy trail escapes. Minimal pack size also saves precious cubic inches.
For ambitious adventures limited by baseweight, the Mythic 200 sets the gold standard. Exceptional warmth-to-weight makes it an always-welcome climbing and hiking companion.
Key Specs
Weight: 28.57 ounces (810 grams)
Limit Temp Rating: 40ºF | 4.4ºC
Price: $$
PROS
✅ Dual zips
✅ Good quality
CONS
❌ Relatively heavy
❌ Not the best hood design
The Marmot Always Summer delivers versatile performance for two-season adventures. Filled with warm 650-fill down, it compresses well for backpacking while still feeling plush around the campfire.
Dual side zips allow climbing in and out with ease. Open the full-length foot zip for extra room or closed for better loft around toes. Extended zipper pulls provide optional blanket-like coverage on chillier nights.
Recycled shell fabrics lend durability without bulk. Down Defender treatments boost weather resistance if conditions turn.
Comfortably rated to 50 degrees, the Always Summer keeps campers content throughout shoulder seasons. its blocky baffles prevent drafts, maintaining insulation where needed.
While hood adjustment cords could use reinforcement, Marmot’s consistent construction delivers reliable warmth.
Bright colors lend fun ambiance for laidback trips. With versatile designs, Marmot remains a top value pick for comfortable nights under the stars.
Key Specs
Weight: 23.28 ounces (660 grams)
Limit Temp Rating: 26°F | -3°C
Price: $$
PROS
✅ Roomy hood for a pillow
✅ Zipperless design
CONS
❌ Temperature rating is a bit optimistic
The Sierra Designs Cloud 35 sleeping bag is different from others because it doesn’t have a zipper. Instead, it has a big blanket-like cover attached, which lets you move around freely, especially if you like sleeping on your side.
It’s designed to keep you warm in all the right places, like your shoulders, and it has a sleeve to hold your sleeping pad in place so you don’t get cold spots.
One cool thing about it is the foot vent that you can adjust to let air in without making you chilly. Also, it has pockets near your shoulders that help keep you warm but not too hot on nights that aren’t too cold.
While the bag is said to be good down to 35 degrees Fahrenheit, we found it comfortable down to about 39 degrees. If it gets colder, you might need to wear extra layers.
For two and three-season backpackers seeking unrestricted movement without quilt complexity, the Sierra Designs Cloud 35 is a good choice for staying comfy and cozy.
Key Specs
Weight: 17.98 ounces (510 grams)
Limit Temp Rating: 40°F | 4.4°C* (Rated by Rab)
Price: $
PROS
✅ Relatively affordable
✅ Eco-friendly
CONS
❌ Temperature rating is a bit optimistic
Rab pushes sustainable design forward with the Solar Eco line. Constructed from recycled fabrics and filled with 100% recycled Stratus insulation, these bags reduce impact without compromising rugged performance.
The Solar Eco 0 strikes an ideal balance for two-season adventures. Minimal quilting reduces cold spots.
Fit and features elevate warm weather functionality. A wide mummy shape allows freer movement than other ultralights. The adjustable hood and neck baffle seal heat, and a 3/4 zipper with internal guard protects from drafts.
While the manufacturer’s 40°F rating seems optimistic, we found the Solar Eco 0 comfortable to around 50°F with base layers. Compression could also be improved.
For eco-minded hikers seeking a bag for two-season lows, the Solar Eco 0 delivers dependable warmth on a budget.
Choosing the best sleeping bag for warm weather requires some thought. Follow this guide to select a bag that will keep you cozy mile after mile.
By considering these factors, you’ll find a 2-season bag perfectly suited to your needs and outdoor adventures.
And remember, you can enhance your sleep system’s warmth by using a sleeping bag liner. Check out some of the lightest sleeping bag liners here.
When picking out a warm weather sleeping bag for camping trips, consider factors like the temperature rating to ensure it can handle cooler nights, whether down or synthetic fill is best for your climate, choosing a lightweight and compact bag by evaluating fill power and extra features like hoods and pockets, and looking at the warmth-to-weight ratio to maximize coziness for the packed size – all to find a bag that keeps you comfortable while backpacking or car camping throughout the summer months.
While a 20 degree bag is suitable for colder weather backcountry trips, it will likely be too warm for summer camping nights as average overnight lows are typically in the 40s or higher – the extra insulation from down or synthetic fills in a bag rated for low 20s isn’t necessary when temps will rarely if ever dip that low, plus the bag compresses less without all that loft so takes up more pack space unnecessarily, so a lighter bag rated 30-50 degrees would perform better for warmer seasons by preventing overheating yet still providing enough warmth on the off chance of a cooler night.
When it comes to choosing materials for a sleeping bag meant for summer use, lighter fabrics with better breathability are ideal to prevent overheating, so options like perluttto nylon or dry-treated down-proof fabrics on the exterior coupled with a minimally insulated interior using down or lightweight synthetic fills that have a lower fill power rating are excellent for warm weather bags since they maintain enough insulation at a low packable weight without making the user feel trapped in an oven through the night if temperatures rise slightly above what’s stated on the bag’s comfort rating.
