The WM MegaLite is our Editors' Choice for the best backpacking sleeping bag. This US-made bag was very close to being the lightest and most compressible option, but was also warmer-than-average among 30F sleeping bags, and offered spacious dimensions and the best feeling internal fabric in our review.
This award winner is on the warmer side of 30°F bags that are available on the market and is packed full of high-quality down. Our side-by-side testing declared that this contender was the warmest 30°F tested in our review (warmer = works better in colder temps).
It features 13 ounces of top-of-the-line 850+ European goose down and offers more loft than is typically found in most similarly rated 30° F bags. However, the new Marmot Phase offers a slightly narrower cut and uses 14 ounces of similar fill-power down.
The WM MegaLite features 13 ounces of high quality 850+ fill and was one of the warmest 30F bags we tested.
Western Mountaineering doesn't provide EN ratings, but in our real-world testing, the MegaLite feels warmer than Mountain Hardwear Hyperlamina Spark 35, the 25°F Sea To Summit Spark III, and REI Co-op Igneo 25, as well as the 20° Kelty Cosmic Down.
The WMMegaLite was far lighter than most bags we tested and in some cases half the weight. The MegaLite weighs 1 lb 8 oz, making it nearly the lightest bag in our review. It is only 2 ounces heavier than the Sea to Summit Spark, but the MegaLite is MUCH more spacious.
The Megalite weighs 1 lb 8 oz, making it one of the lightest bags in our review. It's certainly one of the lighter bags of its temperature rating that can be found on the market. An exception to the Megalite's prowess is the Marmot Phase 20, which is amazingly lightweight. It is only 1-ounce lighter but is rated to a much warmer 20F. This Editors' Choice award winner is only two ounces heavier than the much narrower Sea to Summit Spark III (1 lb 6 oz) which features a lighter 10D shell-fabric and only a quarter length zipper. And, as mentioned above, the MegaLite is warmer.
Despite the MegaLite's comfortable dimensions, it was far lighter than most of the other bags we tested. The high-quality 850+ down fill used maximizes its warmth, yet minimizes its weight. What does this mean for you? Western Mountaineering can use less down weight to achieve the same loft (or in this case, greater), as well as subsequent insulation qualities and warmth.
The WM MegaLite compresses easily into its included stuff sack shown here, maybe a little too easily.
The MegaLite uses a very lightweight 12D shell fabric that Western Mountaineering refers to as "Extremelight". While the fabric is very light, it was tougher than we expected (even after a dozen trips); however, some care should be taken if you are ever sleeping out under the stars or with sharp objects in the tent. Other than that, we never felt like its 12D shell was too light or not durable enough. It's worth noting that the though the shell is light, it continually offered excellent performance, especially in terms of keeping the down inside the bag.
This contender is among the most compressible sleeping bags in our review. For folks wanting a little more room, we feel this bag has the best balance of comfort and space, while still offering an incredibly small packed size.
The MegaLite's included stuff-sack does a reasonable job of compressing the bag, but with an aftermarket compression sack, we were easily able to pack it down 30%-40% smaller. The only bags that were slightly smaller in packed volume were the Marmot Phase, which was maybe 10% more packable, and the Sea to Summit Spark III, which was ever so slightly smaller. In many cases, when compared to most other 20-30F bags, the MegaLite was far smaller by up to half the size (in some cases).
When stuffed into an aftermarket compression sack, the WM MegaLite packed down roughly 30-40% smaller. Once packed down, the MegaLite was easily among the most compressible bags in our review.
Comfort, Spaciousness, and Fit
This sleeping bag was among the most comfortable and spacious bags in our review for several reasons. It features dimensions of 64" for the shoulders, 56" for the waist, and 39" for the feet. Overall, this contender is on the larger side among bags we tested; it even offers extremely comparable overall dimensions to the incredibly comfortable Sierra Designs Backcountry Bed 700. In fact, the shoulder dimensions of these bags are nearly identical; for the closest feel to an at-home bed, the upper body "down-flap" design of the Backcountry Bed offers more freedom of movement in the upper extremities and provides a much more "bed-like" feel.
When comparing the lower body-dimensions of the Backcountry Bed, the MegaLite actually feels more spacious; several tummy and side sleepers preferred the MegaLite to the Backcountry Bed because it was more comfortable to bring a knee fairly high and slightly out to the side. If you are a true tummy sleeper who likes to sleep with one leg nearly straight out to the side, the MegaLite offers good performance. The MegaLite provides the best feeling and coziest interior brushed nylon fabric that was top-notch and by far a conscious favorite among our testers. Most folks who don't typically love mummy-style bags will enjoy the wider dimensions of the MegaLite.
One of the primary reasons the MegaLite wins our Editors' Choice Award is due to its versatility; it's perfect for every adventure that a 30°F rating could be good for. Its spacious enough for car camping or shorter adventures, but light and compressible enough for long-distance backpacking and summertime mountaineering. Because it offers an adequately spacious design, it's easy to add additional layers or utilize it full-length zipper for maximum ventilation on warmer nights.
Features and Design
The MegaLite has one of the best balances of weight and internal spacing; it features high-quality materials to keep its packed size to a minimum, while still offering a healthy amount of room, without being inefficient at keeping the user warm. The MegaLite doesn't offer a ton of extra features in the traditional sense but is designed to be quite functional, offering warmth, lightweight, and compactness, yet it still remains on the roomier side. Western Mountaineering added a stiff material along the length of the zipper which does a fantastic job of minimizing the zipper from catching and possibly tearing the fabric.
Design and Construction
The MegaLite features continuous horizontal baffles that make moving around in the bag an easy feat; these baffles aid in regulating temperature. The down chambers encircle the whole sleeping bag horizontally, from zipper to zipper, allowing the user to shift down either toward the top of the bag for chilly nights or down toward the lower part of the bag for warm nights.
Western Mountaineering focused most of its design in making the MegaLite spacious but also lightweight and compressible and not adding in a lot of extra features. However, one exception to this is a feature we really liked: utilizing a 1" wide stiffer tape along the length of the zipper to reduce the chances of it getting caught and to aid in zipping the bag.
This award winner is an exceptionally versatile bag; its perfect for any 3-season backpacking venture, from single overnights to the John Muir Trail. It's also warm enough for most summertime alpine climbing in places like the Cascades, Sierra, or Tetons. Because of its packed size and low weight, we wouldn't even hesitate to take this bag on long alpine routes like the Evolution Traverse, Torment-Forbidden Traverse, or the Northeast Buttress of Sleese, where you are carrying your sleeping bag on your back while climbing technical ground. We even think the MegaLite is warm enough for late spring ski traverses.
The large cotton oversized storage sack included with the WM MegaLite.
Value and the Bottom Line
This contender is a fantastic bag and our Editors' Choice for the best overall backpacking sleeping bag. If the price fits in your budget, the USA-made MegaLite is almost the lightest bag in the review and offers some of the most compact options. It is among our testers' favorites for comfort with its roomy cut (but not too roomy) and cozy internal fabric. This was by far our favorite all-around 3-season backpacking sleeping bag for most summertime activities. While there are better sleeping bags for specific applications, this would be the bag we would own if we could only choose one. The MegaLite is the best or nearly the best in every metric that we tested.
All of Western Mountaineering's bags are made entirely in San Jose, California, which we think is pretty rad.