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Low weight rules in the big mountains.

Climbing or traversing technical pitches with a massive load dangling behind you is a bad way to go through life. Western Mountaineering created the Alpinlite 20-Degree Down Sleeping Bag for alpine climbers and weight-obsessed backpackers who demand top-shelf quality and bottom-line weight savings. Though it packs the warmth of 850-fill goose down and a full draft collar, the Alpinlite 20 weighs in at just over a pound.

  • Highly breathable nylon shell fabric expels perspiration so that it doesn't condense in the down insulation and cause it to clump
  • Ultra-premium 850-fill down insulation retains your body’s warmth and provides a higher warmth-to-weight ratio than any synthetic-fill insulation
  • Continuous baffles and a down-filled collar prevent energy-sucking drafts from zapping your slumber
  • Wider shoulder girth allows for extra layering in colder environments
  • Western Mountaineering bags are made in the USA

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Western Mountaineering Alpinlite Sleeping Bag: 20 Degree Down

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Here's what others have to say...

How small does the large pack down to?

5 5

I am just spreading the good news:

  • Familiarity: I gave it as a gift but have feedback to share

"Having spent 3 months living outdoors, I could not of stayed sane without this bag. It instantly produces warmth and traps in body heat all night, while its breathable fabric wicks out your sweat. The extra lofty feathers makes your outdoor campsite feel like you are sleeping within a cloud. The bottom foot box provides just the right size to help trap in heat where the shoulders has extra room to move around and stretch out. I'm 5'4" and believe it or not went with the 6' bag and really enjoy the extra space. The best part of all is this bag tucks down into a small and super light travel sack.
The extra money I would normally not be interested in spending was well worth the investment, and will provide me years of great sleep outdoors."

Eric Watford
Expert Gearhead
Instagram: @ericwatford

5 5

2000+ Miles and still fantastic!

  • Gender: Male
  • Familiarity: I've put it through the wringer

I used this bag on my thru-hike of the Pacific Crest Trail. If that's your intent, this bag will be amazing! If not, just know that after 5 months of consistent use, I am still 100% Satisfied.

The PCT is like one giant gear review, not just for your own gear, but you get to see how other's work as well. I believe that this bag is not just survivable to 20 degrees, but COMFORTABLE. I had many friends with other bags, some lighter, some not, but most of the bags with equal ratings, just didn't stand up to this one. Forget the mainstream brands, WM temp rates their bags with accuracy and integrity. Everyone I met with a WM bag, loved it!

Not only was I always warm, I didn't wear much of anything inside it for extra warmth. I only set up a tent on nights with chance of rain or too many mosquitoes. Through the cold of desert nights, the high sierra, winds like you wouldn't believe, and the North cascades in the fall, it was easy sleeping. I used a Z-lite pad the whole time.

I've cowboy camped in windstorms strong enough to make a tent useless and this bag keeps the wind out, frozen water bottles on Mt. Whitney with windchill enough to make everything hurt, this bag warmed me up. Condensation frozen on it like an M&M candy coating, still warm.

The black inside is also nice. If you get this bag wet and have more days to spend in it, the black really helps dry it out in a sunny spot.

Sometimes, it was just too warm for this bag, but it works well as a quilt in those circumstances.

After so many nights hiking, dirty, sweaty, day after day, any bag is bound to get dirty. Yes, it will lose some loft to your body oils and dirt. However, down wash and the instructions on the WM website and it is as good as new with no stench.

Sure, this bag costs a pretty penny, but if your sleep is important to you, you can't go wrong here. This bag combines light weight, fantastic warmth, and outstanding american made workmanship, to create a seriously great 3-season bag!

Responded on

Thanks for joining our community Kyle!
Solid review!

5 5

No more cold spots!

  • Gender: Male
  • Familiarity: I've used it several times

I had a zero degree bag that was too bulky for my backpacking needs, and it had cold spots in the synthetic filling. No more! This bag is incredibly light (I got the long and it's just a couple ounces over two pounds in stuff sack), very small and very warm. I'm perfectly comfortable in 20 degree weather, and although I don't have much occasion to be out in temps colder than that, I'm sure that it would be sufficient with some thermals on in the bag. Expensive, yes, but worth all the money!

5 5

Ridiculously light, absurdly warm

  • Familiarity: I've put it through the wringer

I use this as an Aussie winter bag, which I guess is '3-season' for northern hemisphere people. Whenever I take an old bag to save wear on this good one I miss it. Loft has lasted very well, but I do store it carefully.

What is the weight for this sleeping bag?...

What is the weight for this sleeping bag? The weight is listed on the Western Mountaineering website as 1 lb 15 oz for the regular, not 1 lb 3 oz as shown here.

Best Answer Responded on

Hey Emily,
The correct weights are below:
Short- 1 lb 13 oz
Regular- 1 lb 15 oz
Long- 2 lb 1 oz

We are working to get the tech specs changed on our site.

5 5

first and last down bag

  • Familiarity: I've used it once or twice and have initial impressions

I purchased this bag for myself as I have gotten into backpacking, and was tired of carrying my overweight and oversized kelty synthetic bag. This sleeping bag is just awesome!!! So warm I end up hanging a leg or arm out in 30*f weather! This bag is light, super small when packed, and one of the truest temperature ratings I've ever encountered. you will not be disappointed with this bag even down to the 10-15*f range.

5 5

Sweet bag!

  • Gender: Male
  • Familiarity: I've used it once or twice and have initial impressions

I'm 6'1" 225 and this is the perfect bag. I considered an Ultralite 20 but VERY happy I went with this instead. I need the room to turn & like the option to keep other clothing inside for something warm to wear in the morning.
I used it inside a double walled tent with a Thermarest Z-Lite SOL Sleeping Pad underneath. I wear merino wool socks inside mine along with "whatever" choice of long underwear as it was in the 20's where I lived. I was in my backyard & just wanted to test everything out. I also wore a 80% polyester/20% nylon blend balaclava; Cordura from Ranger Joes (that I noticed was surprisingly better than the merino wool offering from Smartwool)
Staying warm was not a problem in this bag, and I did not cinch up the available ties (there was no need as I had on a balaclava) No cold spots, even when my heels came off the mat & were in direct contact with the freezing tent floor I'd barely notice it, but I did have to scoot back up on the mat where I belonged. I can't tell you from experience (as it is very rare to get into the teens here temp wise) but I have a confidence I could have done so, but I bought the bag for a 20 degree rating only because that's the worst it gets around here & even then its only for a few days max.

The only gripe I had about my night was traffic noise on the adjacent highway I was not used to hearing from inside the house

5 5

One of my favorite pieces of gear I own

  • Familiarity: I've put it through the wringer

Truly one of the favorite pieces of gear i own. Super warm, super light, super packable, super high quality construction. What else is there really to say about a sleeping bag? Outstanding in all regards!

Unanswered Question

From OutdoorGearLab:
"Some of the smallest...

From OutdoorGearLab:
"Some of the smallest premium companies, such as Western Mountaineering, source the highest down from geese that aren't live-plucked or force fed; they collect naturally shed down from molting. Some vegans might consider avoiding down down products or purchase them from a company such as Western Mountaineering, that guarantee no harm to animals."

Can anyone confirm this? I didn't find anything about it on

4 5

A Roaster

  • Familiarity: I've used it several times

This bag is great quality! Western Mountaineering kills it when they make sleeping bags and this bag is as awesome as it sounds, it does, like all down bags, loose down throughout its adventures. All around great bag though except expensive but you get what you pay for!

5 5

Great bag

I love this bag. It has been warm on nights in a makeshift shelter in the 30s. I would feel comfortable taking it down towards that rating in a tent, but not really in a makeshift shelter. Quality of the bag is nice. Packs down small, zippers don't snag often, fabric and baffles feel good. Low weight, yet doesn't feel constricting. Nice bag! Plus made in the USA!

5 5


Looking at Western Mountaineering's website, the weights listed on this description are very wrong. I can't rate since I did not buy, but I picked 5 stars as default.

Responded on

From Wstn Mtn eng.:
5'6"bag 1 lb 13 oz stuff size 7 x 13
6'0"bag 1 lb 15 oz stuff size 8 x 15
6'6"bag 2 lb 1 oz stuff size 8 x 15
This is an excellent bag, the shell is great, but lighter than the Apaches, Antelopes and so on, also produced by wstn mtn eng.

5 5

Fantastic 3-season bag

I have been running the Alpinlite for a few years now. I really like the warmth and lack of weight.
The width is a bonus for me, as I am rather broad across the chest(44 coat size)and am a side sleeper.
I haven't had this bag much below 15*F, but in those cases it was still very warm-I have a hunch I could go into the high single digits with just a base layer and wool cap sleeping in the Alpinlite.
I will never part with this sleeping bag.

hi, are you guys getting more small 5'6...

hi, are you guys getting more small 5'6 sizes??? i need one!!!

5 5

Perfect bag for broad dudes

6'5", 235lbs. Wear a 50L jacket, 34-36 inseam and waist. My arms aren't huge but they won't fit into the "check your blood pressure" thing at Walgreens. Point is, I take up some space.

The Alpinlite was perfect for my size. I move around a bit and never once felt claustrophobic, but I can't imagine having less space. I think I would have been freaking out in Ultralite. The 6'6" version of this bag couldn't have been a better fit. I never got cold at altitude and only got hot once at lower levels, but it was around 50* and I was still wearing a shirt and shorts so that one was on me. All it took was unzipping the bag a bit and it regulated nicely.

I thought I was crazy dropping almost $500 on a bag but this thing is absolutely awesome and it shows in the details: the stuff sack is perfectly sized and the zipper has smart things like a stiff backing so that you don't catch the bag in the zipper. I can't say enough great things about this bag.

I am trying to decide between the Alpinlite...

I am trying to decide between the Alpinlite and Ultralite. I am a side sleeper and toss and turn throughout the night. Avg build guy at 5'9" 160 lbs. Which would you recommend?

Best Answer Responded on

Sounds like the Aplinlite would be to big for you.

Responded on

Do you prefer a little more room for tossing and turning inside the bag or for the bag to move with you as you toss and turn? If you prefer inside the bag, go Alpinlite. If you want the bag to toss and turn with you, Ultralite.

You'll fit fine in both, but the Ultralite is a true mummy bag and the Alpinlite will be a little more roomy but have more internal "dead" space to heat up--so it'll have more down and more fabric and be an ounce or two heavier...

Responded on

Thanks for the quick responses. I normally am a warm sleeper so the empty space is okay. I prefer to have the room when I do toss and turn. The true mummy would be a little to compact I guess. Thanks looks like I will go with the alpinlite.

Correct Weights

Correct Weights

Short 1lb 13oz
Regular 1lb 15oz
Long 2lb 1oz

Responded on

The weights listed by BC are essentially those for the Summerlite (exception being the short model is 1lbs 2oz), which is WM's lightweight, continuous baffle bag with the Microlight XP fabric. Jerimy posted the correct WM published weights for the Alpinlite.

Responded on

It is very interesting how often Backcountry makes mistakes in their specs.