Best Ultralight Sleeping Bag: Weightless and Warm

Dennis Owens
Written by Dennis Owens

As an avid backpacker or first-time explorer, you might have picked up your pack and wondered: how am I going to carry this all the way up the mountain? It might be time to assess your pack and limit the amount of weight you are putting in.

By having a lighter pack, you can go longer and farther on your hikes, optimize weekend trips to traverse more trails, and view more mountains. One simple way to maximize the space in your pack and minimize the weight on your trip is to swap out your bedding accommodations.

In this article, we will cover the best ultralight sleeping bag to bring with you to stay warm and cover more ground.

If you have been shopping around the market you might be overwhelmed by the choices you can make, a wide variety of bags with seemingly infinite options. The reason for this is mind-bogglingly simple, we are all different.

UL sleeping bag

We all experience cold weather differently, have different bodies, and require different bag size needs (did you know there are bags differentiating between men, women, and children?). Even different sleep habit needs are taken into consideration.

Before we review the bag you need, we will go over a few tips to understand ratings and descriptions so you can say “That’s the bag for me!”

Upper, Lower, Extreme and Comfort

Each pack will be rated by the temperature in which they are most suitable for, and these ratings will be different for male and female packs. Lower limits and upper limits are often used to describe male-focused packs.

An upper limit is a standard temperature in which an adult man can sleep comfortably with little to no sweat, and a lower limit is for the same individual to sleep, completely curled up without moving. Extreme for women is sleeping for up to six hours without risk of hypothermia. Cozy, right?

Comfortable is sleeping up to eight hours comfortably in any relaxed position. Now these are just standards, so if you are chilly at night, fully clothed, in bed, with all the windows closed, play it on the safe side.

Sleeping bag UL

Be sure to look up to lowest night time temperature your backpacking destination reaches, and use that as your limit. Being cold while backpacking can make your trip miserable.

Useful tip: You’ve bought the most beautiful bag ever, but you are still chilly at night? You can always add layers of clothes and blankets inside and outside of your bag to raise the temperature rating.

Insulation Type

There are two major types of sleeping bags you can select from, down and synthetic. Down is made up of goose feathers, is expensive, compresses easier for packing and has a fantastic warmth to weight ratio. If you love this bag right it can last for up to 20 years, which is an excellent investment.

The synthetic option is considerably less expensive, they are better in a wet environment and dry quickly. However, they will be heavier and more difficult to wrap up into a backpacking pack.

From one backpacker to another, before you drop loads of money on a down sleeping bag, make sure you are not allergic! If you are, select a synthetic bag and sleep in itch-free comfort.

Zipper Length and Other Weird Things to Think About

So you got the temperature right, but there are still so many options! One that you may not be thinking about is zipper length. Mummy bags, which come all the way up to your head with a hood, come with many different lengths to give the users options.

Ultralight sleeping

It may seem crazy, but a shorter zipper is just one of the ways that manufacturers cut down on weight. Your bag may weigh less without the full zip, but you will be giving up the flexibility of your bag to have maximum ventilation, good for summer and winter hikes!

And lastly, if you are going out in the wild wind and rain, keep in mind durable water repellent (DWR). A good DWR treatment will coat the outer shell and cause the water to bead up and roll off rather than soak in. It might cost you a little more, but if you’ve ever slept in a wet sleeping bag for a 5-day trip, you know it’s invaluable.

Before You Pick

You are ready to go, your trip is scheduled and it’s time to buy gear for the best weekend in the woods. Before you jump to buying ultralight everything, determine what kind of trip you are going on, and whether or not you plan on sharing supplies in your pack.

Backpacking is extremely different than a weekend of car camping, and your packing restrictions will change depending on:

  • proximity to a water source,
  • weather,
  • accessibility to a cooler,
  • miles trekked with the full weight of your pack on your shoulders,
  • and of course, personal preference.

If you are planning on a backpacking trip then your pack will need to be light, carry only the essentials and to optimized your pack select either an ultralight or light sleeping bag.

Buy The Best

You now have looked at all of your options and you are ready to buy the best bag on the market. Here are a few bags that we think are the best with all the options and customizations I mentioned above for your consideration.

Big Agnes Pitchpine UL Sleeping Bag

Big Agnes Pitchpine UL Sleeping Bag

Weight: 2.3 lbs

Dimensions: 67.5”x64”x43”

Price: $349.95-$369.95

Specific Features: This bag has a slip inside of it, allowing you to slide in your mat and insult all that goodness.

Best use: Summer hiking and backpacking trips, rated to go down to 45 but is more comfortable at 48.

Description: Big Agnes Pitchpine UL Sleeping Bag is made out of Pertex nylon, with an insulation type of 850-Fill DownTek. Big Agnes features a full-length zipper, made for 45-degree temperature, and has a max height of 6 ft 6 inches.

Sounds pretty good, huh? This sunflower pack is light weight, best above 50 degrees (though can go to 45) and the product maker suggests a water-resistant treatment to keep the pack dry and toasty. This pack features a top only design, this means that the down is on the top of your bag trapping in the warmth.

Western Mountaineering Summerlite Mummy Bag

Western Mountaineering Summerlite Mummy Bag

Weight: 1lb and 3 oz

Dimensions: 5’6”x 59”x51”

Price: $389.95-$390.00

Specific Features: This bag is not only exceptionally light, it also contains an insulated draft tube, this means that when fully zipped you will have the ultimate wind chill protection.

Best use: Sleeping in temperatures of minimum 32F

Description: Western Mountaineering Summerlite Mummy Bag is true to its name, it’s an ultralight bag perfect for long backpacking trips, but only when trekking through the summer time mountains.

Some hikers use it for three-season backpacking but recommend not going below the mid-30s, especially if you are a larger hiker, as there is not much room for additional layers.

While this bag is a bit pricier than it’s predecessor there are a few key reasons for this. First, the bag is comfortable at a lower temperature which is great for higher peaks, and it is incredibly light.

For backpackers going on the long-haul hikes, this is a light and a compact way to make room for other essentials on your trip. A con to the bag is its dimension, it is a hooded mummy and some testers complain that the hood is not quite big enough for comfort, and it does not expand.

That being said there are a few other benefits to the bag, if you find that you tend to sleep on your side, the stitching on this bag is perfect for you. Summerlite will keep you warm and cozy with its sewing along the bottom.

Related:Western Mountaineering Highlite

Mountain Hardwear Mountain Speed 32

Mountain Hardwear Mountain Speed 32

Weight: 15.7 ounces

Dimensions: 76”x46”x55”

Price: $314.00-$359.98

Specific Features:  Enjoy a down fill with advanced water treatment that allows for maximum warmth in wet conditions. This bag is extremely lightweight with a half zipper and a five chamber hood to trap heat.

Best use: sleeping in the mid 30F temperature range

Description: With their advanced Ghost Whisperer fabric shield, Mountain Hardwear Mountain Speed 32 can stay comfortable in the mid-30s range. Packing down to almost this size of a Nalgene water bottle, you can feel good about saving room in your backpacking pack. It’s warm for its weight and can be a good choice for a three season bag.

Hardwear Mountain Speed can go into the same cold range as Summerlite but runs a little less expensive, there are a few key reasons for this. One is that the bag does not offer a full zipper, so in warmer summer hikes you won’t get the full ventilation and may overheat.

Also in order to save weight the mummy bag is cut tightly, meaning there isn’t a lot of room to add layers into the bag if you find your self-cold at night.

One last thing to note about this bag is it’s relatively low reviews. This is due to complaints around the zipper performance.

It seems that backpackers are struggling with the zip getting caught, it being too flimsy and overall too small. This can be frustrating in the middle of the night when you find yourself stuck in a mummy bag, or worse zipped out of it in the cold.

Nemo TangoTM Solo Down Comforter (30F)

Nemo TangoTM Solo Down Comforter (30F)

Weight: 1.16 lbs

Dimensions: 76”x46”x46”

Price: $299.95

Specific Features:  This rectangular shaped down comforter features DownTek 700-fill-power down and has excellent water-repellent treatment to keep you warm and dry.

It is not a mummy bag but features a snap-on hood for colder nights. Unlike other down comforters, this packs down small and weighs less.

Best use: sleeping in over 30 F and low 40 F

Description: Backpacking, most comfortably rated in the upper 30s and low 40s, but with an additional slipcover can be easily used in low 30s.

What big time backpackers love the most about Nemo TangoTM Solo Down Comforter (30F) are the roominess and versatility. Unlike a mummy bag, hikers find that they can easily sleep on their sides and toss and turn throughout the night without fear of warmth escaping.

The snap on hood provides comfier additional heat, and the fabric of the comforter is soft and comfortable.

Some say that they wish the comforter would allow for a wider sleeping pad, at its optimal use the bag is tucked into a 20 or 25 in wide sleeping pad.

Finally, there are some concerns about there being bare spots in the down where you can feel the cold through.

Related: NEMO Tango Solo and Slipcover Combo

Marmot – Plasma 15 Long Sleeping Bag

Marmot - Plasma 15 Long Sleeping Bag

Weight: 1 lb

Dimensions: 60”x58”x43”

Price: $494-$698

Specific Features:  This bag features 875-fill goose down with Down Defender water-resistant treatment to keep you dry and warm.

Marmot – Plasma 15 Long Sleeping Bag special feature is that the mummy bag has Insotect flow vertical baffles, this is meant to help with keeping both your core and extremities warm in cold weather. There are also two-way zippers and an insulated draft tube.

Best use: 3 seasons, low temperatures of minimum 15 F degrees

Description: Marmot has designed this bag to go as low as 15-degrees F, it is normally used for three-season backpacking, but some users have brought it on winter camping.

Now this bag is on the pricier end, but the simple reason is that it can go in extremely low temperature without having a lot of weight added to your backpacking pack.

Most users have noted that they are heated from their core and the bag directs that heat down to their fingers and toes, which is quite the life saver on cold nights. This bag also has high ratings on durability and its water resistant treatment.

Like most mummy bags the biggest complaint is that for larger chested hikers, this bag can be a bit too snug and limit the amount of movement at night.

Related: Outdoor Vitals Summit 20 Down Sleeping Bag, Mountaintop Ultralight Natural Down Sleeping Bag

Sierra Designs Backcountry Bed Elite 2-Season Sleeping Bag

Sierra Designs Backcountry Bed Elite 2-Season Sleeping Bag

Weight: 1 lb 11 oz

Dimensions: 60”x58”x44”

Price: $337.46-$559.95

Specific Features:  Unlike most bags on the market, Sierra Designs chooses to go with a zipperless design in their integrated comforter. It is insulated with 850 fill Duck DriDown, comes in a multitude of sizes and has a self-sealing foot vent.

Best Use: 2 seasons, 30 degree

Description:  Sierra Designs Backcountry Bed Elite 2-Season Sleeping Bag was built for backcountry hiking and camping and has a featured down-filled quilt flap that can be folded down to your waste or pulled all the way up to your neck. If you are a restless sleeper who ranges from hot to cold throughout the night, this Spring to Fall bag is for you.

Sierra Designs choice to use no zippers in their pack has actually pleased quite a few campers, noting that they could stretch out and easily move around without fear of zippers pulling down.

While at first look the design may seem a bit silly, reviews and testers note that they are warm, comfortable and able to move and adjust as needed. The sides are made extra wide which allows for plenty of rolling around and is perfect for the vast temperature range that is known for backcountry camping.

Rab Neutrino Endurance 600 Sleeping Bag

Rab Neutrino Endurance 600 Sleeping Bag

Weight: 15 ounces

Dimensions: 72.8”x27.5”x20.5”

Price: $440.00

Specific Features:  The Neutrino Endurance bag is made with minimum weight and packs size without giving up any precious warmth. It is a snug mummy shaped bag with 800 fill European goose down with both left and right-hand full zipper options added.

The bag is rated at 7 degrees F, making it the lowest temperature rated in our options. A cool feature unique to this bag is that it zips into other Neutrino Endurance bags if you want double your space or to cuddle with your partner, this bag offers that without losing warmth.

Best Use: Rab has designed this bridge for alpine climbers and can be used on light weight mountaineering trips.

Description: This ultralight bag can go with you to temperatures as low as 7 degrees and is rated at the 0-10 range. The Pertex fabrics on the outside of the back offer ideal protection for cold and damp climates and is a mummy tapered shape to pack up small.

Users of this bag praise it’s warmth and it’s ability to keep them dry in wet climates. What this bag does different, is that it went one step further on its insulation, it repeals any built up condensation from clumping and seeping in so you can be sure you will be dry all night.

If you are worried that the temperatures you are hiking in are going to plummet, leaving you out in the cold, this is the bag to bring. Winter expedition bags tend to run expensive and are heavier, this reasonably priced back keeps the heat in and the price down.

How Is Your Sleep Gonna Be?

These are just a few products out there on the market, and as I said before you have many options to choose from and many specifications to look over.

Choose your ultralight sleeping bag

What is essential in picking out your bag is not necessarily the most expensive or highest rating, but rather our own personal sleeping habits and the need for warmth. We are all different, so just because the bag is rated best on market, does not mean it is best for you.

After purchasing your bag take it on a few car camping trips before jumping out and onto a chilly trail to make sure it is the right fit for you. There are a lot of bags out there, but we want to know what you think is the most versatile, if we’ve missed one in our review tell us in a comment below!

Dennis Owens
Dennis Owens

Dennis Owens is a graduate of National Camping School and REI Outdoor School. He knows everything about what gear to take with you, how to plan your trip to stay safe and what to do if you get lost in the mountains. We are lucky to have Dennis with us as he is a ‘walking encyclopedia’ when it comes to the wilderness.