If you need an outdoor sleeping bag that will perform well in any weather conditions, check out this selection of the best lightweight synthetic sleeping bag from the best-known outdoor brands.

Usually, when people search for a sleeping bag to carry on the trail, they tend to focus on down-fill sleeping bags. And this is because of their weight and compressibility. But there may be situations when a synthetic sleeping bag would be more appropriate. During long hours in wet conditions, a down fill might gradually lose its insulating property and become damp and heavy.

As you know, synthetic insulation preserves its properties even if it gets wet. It also dries faster than a down fill or a cotton fill, so we have decided to make this list.

You have a variety of options here. Some have clever designs, so you can have several variants in one product. This means i) double-wide and solo sleeping bags and also ii) synthetic sleeping bags with a variety of temperature ratings.

A double-wide sleeping bag can be a great option if you are with a partner. Such a bag is both lighter and more compact than when you would use two separate solo sleeping bags.

Our List Of Best Lightweight Synthetic Sleeping Bags

The sleeping bags in the list below are ordered by weight from heaviest to lightest:

We’ve done our best to include as many different designs as possible; we hope you like them:

1. Big Agnes Sleepy Bear 35 Double-wide Sleeping Bag

  • Weight: 5.10 lbs
  • Temperature Rating: 35 F
  • Dimensions: 78″ x 50″
  • Pack Size: 12″ x 10.5″

This is a double-wide sleeping bag. For its overall size and features, it is still reasonably light and could be carried on the trail. The weight is 5 lb 10 oz (2.55 kg), which you might think is heavy, but wait till you see all its features.

The shoulder girth is 128 inches (325 cm) and slightly tapered, so the foot perimeter is slightly smaller at 106 inches (269 cm). So it can be described as semi-rectangular.

Top Pick


  • It’s extremely comfortable
  • Great packed size
  • Not too heavy
  • Nice double hood design


  • Not the best temperature rating

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You have a multi-denier and hollow-core Fireline Core synthetic insulation. It provides loft, structure, and warmth even in damp conditions. It comes with a sleeve for the pad, and you can use either a double wide 78 x 50 inches pad or two single pads at 78 x 25 inches. Note that it has a massive and warm hood with insulation.

The bag is with a soft-shell polyester ripstop fabric on top. Inside is a cozy polyester lining, all with a PFC-free, water-repellent finish. The official temperature rating is 35 F (2 C), so the bag is for three-season use. It can be compressed to (L x D) 12 x 10.5 inches (30 x 27 cm). The length is such that it fits users of up to 78 inches (198 cm).

2. Exped MegaSleep Duo 25 Sleeping Bag

  • Weight: 4 lbs
  • Temperature Rating: 42.8 F & 26.6 F
  • Dimensions: 82.7″ x 63″ 
  • Pack Size: 11.8″ x 7.1″

This Exped MegaSleep Duo 25 Sleeping Bag is here because of its synthetic construction, but it is incredibly versatile. It could be described as a 4-in-1 bag.

  • It has two temperature ratings. The two halves have two different temperature ratings, so you can use one as the top layer.
  • It is designed to be used as a double-wide and also as two solo sleeping bags.

Note that you can use those two halves as separate blankets as well. As for the temperature rating, one side has a 42.8 F (6 C) rating, and the other is 26.6 F (-3 C). So if you use any of the two halves as a solo pad, you will have two different ratings.

Best For Two People


  • Plenty of space for two people
  • It packs down pretty well
  • Extremely comfortable


  • Not for cold weather
  • No compression sack
  • No hood

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The bag is rectangular and without a hood. The fabric is a moderately durable 40D ripstop nylon, Oeko-Tex 100 certified. The liner is 40D nylon, and it is also Oeko-Tex 100 certified. The insulation is a 100% polyester Texpedloft microfiber.

You have a 3D anti-snag draft tube along the entire length of the zipper. There is also a central snap at the head ends to reduce drafts caused by your partner.

Here are some numbers. The weight is 64.2 oz (1820 g). The dimensions are 82.7 x 63 inches (210 x 160 cm). The packed size is very impressive, it measures (L x D) 11.8 x 7.1 inches (30 x 18 cm), but they do not include a compression sack, so to reduce it to such a size, you will have to buy one.

3. Big Agnes Lost Dog Sleeping Bag

  • Weight: 1.15 lbs
  • Temperature Rating: 45 F
  • Dimensions: 78″ x 25″
  • Pack Size: 6.5″ x 5.5″

Here you have a complete series with several sleeping bags of different temperature ratings, and they are all built in at least two sizes, regular (R) and long (L). So you have plenty of options to fit your body size and the environment where you plan to use the bag.

The bags come with FireLine ECO Synthetic Insulation, a 100% post-consumer recycled polyester. This material is with a high weight-to-warmth ratio. You have low-denier fibers, tightly woven and with high loft and compressibility.

Best Weight


  • Loads of size options to choose from
  • Comes with a padded sleeve
  • Great compressed size


  • The weight, but this is only for the versions for lower temperatures

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The external shell is a nylon ripstop with a water-repellent finish, and a polyester lining is inside. These bags are also equipped with inner loops for extra layering. They come with a Flex Pad Sleeve design, a stretch construction that can accommodate multiple pad widths.

To get some idea about numbers, in the case of the Big Agnes Lost Dog 45 Degree Sleeping Bag, you have a temperature rating of 45 F (7 C). Its weight for the two sizes is:

  • Weight:
    – R: 1 lb 12 oz (794 g).
    – L: 1 lb 15 oz (879 g).

The following numbers will also be useful to know:

  • Compressed bag size:
    – R: 6.5 x 5.5 inches (17 x 14 cm).
    – L: 6.5 x 6.5 inches (17 x 17 cm).
  • Girth (shoulders/hips/knees):
    – R: 69/60/49 inches (175/152/125 cm).
    – L: 72/63/52 inches (183/160/132 cm).

4. Big Agnes V Notch UL 40 Degree Sleeping Bag

  • Weight: 1.9 lbs
  • Temperature Rating: 40 F
  • Dimensions: 77.9″ x 59″
  • Pack Size: 5.5″ x 6″

This sleeping bag can be described as ultra-lightweight and ultra-packable. And they build it in two sizes.

  • Weight:
    – R: 1 lb 8 oz (680 g).
    – L: 1 lb 9 oz (709 g).
  • Compressed size (L x D):
    – R: 5 x 6 inches (13 x 15 cm).
    – L: 5.5 x 6 inches (14 x 15 cm).

It’s made with a high-quality synthetic 80% recycled PrimaLoft Hi-Loft Ultra Silver insulation. The two sizes are for users around 6 ft (183 cm) and 6 ft 6 in (198 cm). The temperature rating is 40 F (4.4 C), so this is a sleeping bag for 2.5 – 3 seasons.

Best Pack Size


  • Exceptionally lightweight
  • It’s extremely compact
  • Made with quality materials


  • No compression sack
  • Not great in cold weather

Available from:

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This is a 70 inches (178 cm) YKK #3 locking zipper. The shell and lining fabric is DWR nylon ripstop. You have a two-way zipper, so you can open it independently from the bottom to have some ventilation.

The bag is mummy style, and with an ergonomic foot box, you have interior loops for extra liners. The circumference (chest/hips/knees) is 59/53/36 inches (150/135/91 cm) for the R size and 62/56/39 inches (158/142/99 cm) for the L size.

Final Thoughts

So although the list given here is relatively short, you still have plenty of options to find the best lightweight synthetic sleeping bag. As mentioned, some are just representatives from a series of bags, and some are multi-functional with a several-in-one design.

A hood is a good idea if you know you will be camping in a cooler environment. On the other hand, having a hood is not great if you want a bag that can be fully unzipped and used as a blanket.

There are differences in the weight and packed size, so bear this in mind if you plan to carry the sleeping bag on the trail or transport it on a bicycle.

You might want also to read about the best backpacking sleeping quilts. This is the lightest option to carry on the trail. You should also check out this list of very light best down rectangular sleeping bags.

Let me know if you have questions; there is a comment box below.

Fun Outdoors Team

The FunOutdoors team is comprised of seasoned writers and editors with a passion for outdoor living. 

Happy trails!

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