Western Mountaineering Megalite Mummy Sleeping Bag: Sleep Like A Mummy

Written by Kane Dane

If you will be spending much of your time backpacking or camping in the wilderness, it’s essential to ensure that all your equipment and supplies are available to keep you warm and dry. If you are making a plan of what items to acquire, a sleeping bag should top the list as it will be quite impossible to sleep without it.

Part of enjoying your expeditions involves getting the right gear to give you that comfort you need and preventing the cold from freezing you to the bones. This is where the Western Mountaineering Megalite Mummy Sleeping Bag can sure come in handy!

You will also need to consider the place you will be camping, the weather conditions, and what other accessories you would require. Also, you will need to factor in aspects such as weight and the temperature ratings of your gear, as backpacking ventures always require light weight load.

You’ll also need to consider the volume of your gear, its loftiness, the type of insulation used, among other important factors. The Western Mountaineering MegaLite Mummy Sleeping Bag is a large cut gear for bigger individuals or people looking for plenty of space. If you have a phobia of being closed in, or perhaps a broad set of shoulders, you do not need to worry.

Product Specifications

  • The Western Mountaineering Megalite Mummy sleeping bag weights 1 lb 8 oz / 0.68 kg in its regular length.
  • It has 12 oz. of 800+ Down Fill and 30 degrees F Rating.
  • The Western Mountaineering Megalite Mummy sleeping bag is compressible and packs easily.
  • It has top collar.
  • This sleeping bag has a shoulder girth of 64 inches, hip girth of 55 inches and foot girth of 39 inches.
  • The maximum user height is 6 foot in the regular version and 6 foot 6 inches in the long version
  • Unfortunately this sleeping bag is not water resistant.

Check the price on Amazon

The MegaLite is an 850+ down fill bag with 39” foot girth and 64” shoulder girth. All you have to do is to lay back and enjoy the soft. Fluffy down on the night down to thirty degrees Fahrenheit. In this review, we are going to go over all of the important details of this sleeping bag, how it can work for you, and give you the pros and cons of it.

We will also share with you what the users think, and show you a few reviews of sleeping bags that compare to this one so you can be knowledgeable of what is out there and their features. Let us get started!



Apparently, this product is 20 x 12 x 8 and weighs 3.4 pounds when shipped. In the box, you will find the sleeping bag, as well as the stuff sack. You will need to unroll your sleeping bag and shake it out once it arrives to you. It is also best if you launder it before your first use. Read the directions on laundering it first.

Design and Durability

This product utilizes a lightweight 12D shell material that the company refers to as the “Extremelight.” While this is a light fabric, it will be tougher than you would ever expect (even after numerous trips). Nevertheless, it’s imperative you should be careful when sleeping out of your tent or with sharp objects as this could easily penetrate the fabric.

Western Mountaineering Megalite on table

Other than that, you’ll never feel like this shell is too light. It’s worth nothing that this tough shell is light as it will continuously offer excellent performance, particularly in term of holding the down together. This sleeping bag has one of the greatest balances if internal space and weight.

It features materials of high quality which minimize its packed size while still providing a healthy amount of space without being inadequate at keeping you warm. The bag doesn’t contain a ton of “added features” in the traditional way, yet it remains on the roomier end.

Western Mountaineering included a stiff material along the zipper that does an excellent job of reducing the zipper from sticking and possibly cutting the fabric.


The MegaLite is on the warmer side of the thirty-degree bags which are currently available on the market. This is one of the warmest 30oF bags (warmer = performs excellently in colder temperatures).

guy inside a sleeping bag

The sleeping bag features thirteen ounces of 850+ goose down and provides more loft compared to most bags rated 30oF.

Pack Size

The MegaLite mummy is one of the most compressible gear you can own. For those in need of extra room, this sleeping bag is the right balance of space and comfort and offers an amazingly small, packed size. The included stuff sack does a good job of compressing it, but with the aftermarket compression sack, you will be in a position to pack it down thirty to forty percent smaller.

The only sleeping bags that are slightly smaller in packed size are the Marmot hydrogen that is approximately ten to fifteen percent more pack-able, and Sea to Summit Spark III which is somewhat smaller. In most cases, when compared to other 20 to 30F sleeping bags, the MegaLite is far smaller by about a half of the size.

Technical Specs and Ease of Use

Weight 1 lb 8 oz / 0.68 kg (Regular)
Special Features 12 oz. Down Fill, 30 degrees F Rating, Less than 2 lbs, Packs easily, Top Collar
Best Use Camping, hiking, backpacking, trekking
Brand Western Mountaineering
Shape of sleeping bag Mummy
Type of insulation 800 + down
Fill Weight 12 oz / 340 g
Shoulder girth 64 inches
Hip girth 55 inches
Foot girth 39 inches
Max User Height 6 ft 0 in (Regular), 6 ft 6 in (Long)
Temperature rating 30O
Water resistant NO
Temperature range 21 to 30oC

Using this sleeping bag is so easy, anyone could do it. When you are ready to get inside, take it out of the stuff sack and unroll it. Unzip the side and slide in and then zip yourself in.

If you need some ventilation, you can unzip an area so you have more air flow. When you are done using the sleeping bag, simply roll it up and stuff it back into the stuff sack and continue on your outdoor adventure!


This bag weighs 1 pounds, 8 ounces making it one of the lightest bags available on the market. It’s definitely one of the lightest gear of its temperature rating. Despite its comfortable dimensions, the features associated with the MegaLite are also light enough that their impact on the general weight of the product is almost negligible.

The high-quality 850+ down fill fitted into the bag, helps to maximize its warmth and still manages to minimize weight. So, what does this mean? The manufacturer can utilize less down weight to attain the same loft (or greater), as well as insulation and warmth.

Western Mountaineering Megalite hood

This product utilizes a lightweight 12D shell material that the company refers to as the “Extremelight.” While this is a light fabric, it will be tougher than you would ever expect (even after numerous trips). Nevertheless, it’s imperative you should be careful when sleeping out of your tent or with sharp objects as this could easily penetrate the fabric.

Other than that, you’ll never feel like this shell is too light. It’s worth nothing that this tough shell is light as it will continuously offer excellent performance, particularly in term of holding the down together.

Best Application

The Western Mountaineering MegaLite bag is a versatile gear for use in the outdoors. This sleeping bag is suitable for any three-season backpacking adventure, from the single overnight to the thru-hikes. The MegaLite is warm enough for the summertime alpine climbing in areas such as the Sierra, Cascades, or Tetons.

Western Mountaineering Megalite on porch

Due to its light weight and packed size, you wouldn’t even hesitate to carry this bag in the long alpine treks such as the Northeast Buttress of Sleese, Torment-Forbidden Traverse, or the Evolution Traverse, where you will be carrying your bag on your back as you take on the technical grounds. The MegaLite is even warm enough for the late spring ski traverses.

Value for Money & Guarantee

The sleeping bag is a great choice for a three-season backpacking expeditions and for approximately $450 you will see that it is still a big value. To make it even better, there is a wide range of sleeping pads that can be paired with it, to both protect it from the ground and also to add another level of insulation and comfort.

Western Mountaineering offers a fairly substantial guarantee on their products. The official website states that all of their products are covered against defects for an unlimited time.

Western Mountaineering Megalite in living room

The guarantee does not cover normal wear and tear or improper usage, such as punctures, rips, burn holes and the like. They also state that they will only repair, clean items, so you’ll want to be sure to properly clean your bag if you send it for repairs.

Similar Products/Competitors

Below are three product reviews of similar sleeping bags on the market for you to compare to the one we are reviewing. Pay attention to the features, materials and other additions that make these stand out and then compare them to the Western Mountaineering sleeping bag.

Sea to Summit Spark SP II Sleeping Bag

sea to summit spark sp

The Sea to Summit Spark SP II Sleeping Bag is a mummy shaped bag that is made of nylon lining and has a shell made of Ripstop nylon and has down filling inside to keep you warm. With a temperature rating of 35 degrees, this 3 season bag will keep you satisfied on most backpacking trips!

This bag comes in 2 sizes, Regular and Long, so taller people can fit in it with ease. The stuff sack holds 3.3 liters, of which 2.9 liters is the compressed volume of this sleeping bag. The stuff sack is 5 x 10 inches.

You might want to purchase the separate sleeping bag liner to fit this sleeping bag so you have more versatility in using it. You do not need a liner, but if you find yourself in need of one, there is one to match this bag. Users loved this bag because it kept them warm, was stylish, and not too expensive.

Sierra Designs Dri Down Mummy Sleeping Bag

siera designs dridown mobile

The Sierra Designs Dri Down Mummy Sleeping Bag is made of 800 fill Dri Down and has dual sliders to vent the bottom of the bag while you are inside of it. The openings are reinforced with down baffling to keep heat in and cold air blocked. It also has a center zipper.

This bag comes in 2 sizes, Regular and Large, and users like it because it is warm, designed nicely, and keeps their head from getting cold. For a 3 season bag, this works perfectly! Overall, users liked this bag, except the regular down filling, but they stayed warm, had a smooth experience in using the sleeping bag, and would refer it to others in the future!

Western Mountaineering Summerlite Mummy Sleeping Bag

The Western Mountaineering Summerlite Mummy Sleeping Bag has a temperature rating of 31 to 40 degrees F, and is mummy shaped and very light in weight. Made with 850 fill down, you are sure to keep warm all night long, down to near freezing temperatures.

This sleeping bag features insulated draft tube to keep cold air out, as well as continuous baffles that go all through the sleeping bag. With the narrow cut at the feet, you maximized the heat efficiency, and you will love the 4 inch loft so you stay comfortable! This sleeping bag comes in 3 sizes; Regular, Long and Extra Long.

The regular fits up to a height of 5 ft, 6 in. The long one fits up to 6 feet tall, and the extra long one fits up to 6 ft, 6 in, so that nearly anyone of any height can use this sleeping bag! Users like it because not only did they stay warm, they even felt a little toasty and had to vent the bag out. They also loved the extra space, especially in the foot bed area.

While the zipper can snag, users loved the draft tube and loved that it stayed dry in wet weather. You can also choose from a left or right side zippers, which only enhances the features of this sleeping bag. Overall, users rated it highly despite it being a little pricey, but users said it was definitely worth the money to have a dependable sleeping bag on their outdoor adventures!


One of the greatest reasons why the MegaLite is suitable for all your outdoor applications is the aspect of versatility. The bag is suitable for every adventure that a thirty-degree rating could be perfect for.

The bag is spacious enough for short adventures, and car camping, and also compressible and light enough for long-distance summertime mountaineering and backpacking. Since the MegaLite provides an adequately spacious design, it’s possible to include additional layers or use its full-length zipper for ventilation during warmer nights.

The EXTREMELITE HighLite, MityLite, SummerLite, UltraLite, TerraLite, or MegaLite Sleeping gear will help the bulk of your backpack as well as your weight. All the six sleeping bags are fitted with 850+ F-power down, the most compressible and lightest available.

sleeping bags in nature

Nothing is as significant to the function and quality of a sleeping bag as its insulation. This is why these items have the best. The shell fabrics are treated using the Durable Water Repellent finish to ensure that they do not malfunction when exposed to moisture as the DWR can shrug off any dew or condensation.

The good thing about the Durable Water Repellent is that it’s possible to reapply whenever it wears thin. The shells are manufactured from new lightweight fabrics which weigh as little as 0.85 ounces for every square yard. By their very nature, the unrestricted and total lofting of the down fill is achievable.

The Western Mountaineering sleeping bags, the Megalite included have a storage sack and a stuff sack. The company has been handcrafting these bags for over four decades. One great advantage of these products is that they are guaranteed against the manufacturer’s flaws for an extended period.


  • Warm
  • Breathable
  • Small pack size
  • Big fully lofted size
  • Has 30 degree F rating
  • Includes a top collar


  • Zipper occasionally sticks on the fabric
  • Cost hundred of dollars
  • Only comes with Black interior

Before deciding to buy a sleeping bag, make sure you do your research so as to determine what features you need. Look at the fabric used, the types of insulation, the temperature rating, the additional features it possesses, and its cost. If all these coincide with your needs, then you can make your purchase.

You also need to know that there are numerous options to pick from so it’s imperative to choose the one that offers the best value for your money. For a temperature rating of 30oF, the MegaLite is something you will be proud to own.

Western Mountaineering Megalite Mummy Sleeping Bag
  • Weight & Size
  • Packaging
  • Design & Durability
  • Insulation
  • Warmth
  • Value for the Money


The Western Mountaineering MegaLite Mummy Sleeping Bag is the best backpacking sleeping gear for use in your outdoor expeditions. If the price of this product fits your budget, you should not hesitate to purchase it. The MegaLite is one of the lightest products that offers some of the most useful features you would expect to get from a sleeping bag. With its roomy cut (although not so roomy) and cozy fabric, it’s a favorite product for comfort.

Apart from that, the MegaLite is a perfect all-around three-season backpacking bag for all your summertime adventures. While there is other, better sleeping gear, this one provides the versatility you so much desire from an outdoor sleeping bag. This is nearly the best (or perhaps the best) gear in every metric you subject it to.

User Review
4.5 (2 votes)

So, have you made a decision about the bag you will purchase? Do you have any suggestions or recommendations about some of the products available on the market? Please let us know. Feel free to include your view in our comment section below.


Kane Dane


  • The Sierra Designs DriDown Mummy Sleeping Bag is one of kind sleeping gear. Its top performance is guaranteed at an affordable price range. This is a good purchase, Paul.

  • Western Mountaineering is well-known for producing top-quality sleeping bags. The brand offers high-quality features and superior performance.


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