Long-term review: Western Mountaineering AstraLite || Very warm & light

In a one-week period in April I fielded three inquiries about the Western Mountaineering AstraLite, which was released in spring 2018 and which I’ve used for about 30 nights while scouting the Yosemite High Route in August, guiding trips in Sequoia-Kings in September, and enduring cold-and-wet conditions in West Virginia in May. I will use it again in July in the High Sierra, but intentionally I’m not taking it to Alaska this month.

I can’t recall another quilt that garnered such interest, and I attribute that entirely to the manufacturer. Western Mountaineering has been making premium down sleeping bags and insulated clothing since the early-1970’s in San Jose, Calif. And it’s still owned by Gary Schaezlein, who co-founded the brand with Jeff Jones.

Long-term review: Western Mountaineering AstraLite

The AstraLite is the first sleeping quilt from Western Mountaineering. It weighs a sweet 16 ounces (454 grams) and is appropriately rated to 26 degrees (-3 C), making it perhaps the warmest-per-weight quilt on the market. It’d be ideal for:

  • Mountain West: May through mid-October; and,
  • Desert Southwest: Spring, fall, and most of the winter.

I would not recommend it for humid or rainy climates. If you backpack primarily east of the one-hundredth meridian or west of the Cascades, look elsewhere.

As a top quilt, the AstraLite performs wonderfully in a hammock or in a ground system (if you are a calm sleeper, utilize its pad attachment system, and/or use it inside of a bivy sack).

The AstraLite is a premium-grade product: made in the USA, 850-fill humane European goose down, 4.5 inches of loft, 7d and 10d shell and liner fabrics, and an insulated neck yoke — plus top-notch craftsmanship and customer service.

But you’ll pay for it. At $420 MSRP, the AstraLite is universally more expensive than the best offerings from younger direct-to-consumer brands like Enlightened Equipment, Nunatak, Katabatic, and ZPacks.

AstraLite vs NanoLite

The AstraLite was launched simultaneously with the Western Mountaineering NanoLite, which is lighter (11 oz) but less warm (38 degrees). If I were to review the NanoLite specifically, my comments would be mostly the same.

The AstraLite and NanoLite are identical in every way besides loft (which is a function of their respective fill weights and baffle heights). They share the same down quality, shell and liner fabrics, baffle construction, pad attachment system, dimensions, and neck yoke.

If I backpacked primarily in the warmer desert Southwest, I’d probably get more use out of a NanoLite, because it’s comfort range overlaps more with with the prime backpacking months. But in the Mountain West, it’d be suitable only for the warmest summer nights, or for warm sleepers.

The NanoLite is lighter (and less warm) than the AstraLite. In the Mountain West, it’d be a summertime-only product. It’d get more use in the warmer Southwest.


In the summer my sleeping comfort is about 10 colder than the average backpacker. I get scarily thin and I usually cowboy camp, making me more vulnerable to radiant heat loss and nighttime katabatic winds. To push a sleeping bag or quilt to its advertised or EN-tested comfort temperature rating, I expect to sleep in most of my clothing (hiking shirt, shorts and underwear, trekking pants, fleece mid-layer, and hooded down jacket).

Nighttime temperatures in Yosemite in August were in the low- to mid-30’s; in Sequoia-Kings in September, mid- to high-20’s; and in West Virginia in May, low-40’s and wet. I was comfortable on all trips, and concluded that the AstraLite’s 26-degree rating was fair and appropriate.

To remain comfortable on the September trips, when the lows were regularly at the AstraLite’s comfort limit, I swapped the Big Agnes Insulated AXL (my review) for a warmer Therm-a-Rest NeoAir XLite, and I more often used the AstraLite’s draft closure system.

I see little sense in a quilt that is rated for temperatures colder than the high-20’s. Beyond this threshold, high-loft head insulation is absolutely mandatory, and at that point you might as well use a traditionally mummy bag, which is simpler and less vulnerable to drafts.


The AstraLite and NanoLite are both available in two lengths:

  • 5’8″ version for sleepers less than 6’0″ tall; and,
  • 6’4″ version for sleepers between 6’0″ and 6’6″.

With quilts, it can be difficult to make sense of the width spec, which Western lists as, “up to 68 inches.” More helpfully, the AstraLite and NanoLite are based on Western’s Ultralite mummy bag, which has a slimer profile of 59, 51, and 39 inches at the shoulder, hip, and foot, respectively.

Insulated draft yoke

The chief downside of sleeping quilts is their draftiness. Active sleepers have an especially tough time, constantly revealing their non-insulated backsides, or breaking the seal between the quilt edges and the pad. But even calm sleepers like me lose heat around the shoulders and neck.

The AstraLite reduces drafts with a comfortable neck yoke. To employ, snap the two top corners together and tighten the cinch cord that runs through the quilt’s top hemline.

The yoke makes a significant difference in nighttime comfort, especially when temperatures are approaching the quilt’s comfort limit. But it still does not rival the cocoon sensation of a mummy bag or the warmth of the hideaway hood on the (notably heavier) Sierra Designs Nitro Quilt.

The neck yoke reduces drafts by cinching gently around the neck.

Pad attachment system

The AstraLite has three 3/8-inch elasticized grosgrain webbing loops on its underside, through which a sleeping pad can be inserted. This creates a seal between the edges of the quilt and the sleeping pad, making the quilt function more as a true top bag.

The loops are simple and effective, but they are a little fussy. I found it best to slide a partially inflated pad through the loops, adjust as necessary, and then fully inflate the pad.

I removed the uppermost loop, which is a few inches below the top hemline. When this loop is engaged, it feels as if you’re attached to a backboard, which defeats a primary selling point of quilts: their free-form nature.

On the back of the AstraLite, there are three 3/8-inch elastcized grosgrain webbing loops. (I removed one.) A sleeping pad can be inserted into them, to create a tighter seal between the quilt and pad.
Side view of the pad attachment system when engaged.

Moisture resistance

Based on its performance in the High Sierra last year, I was inclined to give the AstraLite a hearty thumbs-up. It offers a lot of warmth for just 16 ounces. But after using it for two 3-day cold-and-wet trips in West Virginia, my endorsement is now qualified.

I don’t know the exact cause, but the AstraLite (and presumably the NanoLite, too) floundered in consistently wet conditions. My quilt never came into direct contact with moisture (e.g. splatter, a dunking), but it was wetter than other bags: clients observed it during a mid-day “reset dry,” and it was very evident to me after the trips when I was drying my quilt and their demo bags.

As a result of it absorbing ambient humidity, the AstraLite was far less warm, performing more like the NanoLite than a dry AstraLite. This issue had presented itself slightly on my earlier trips, but in the semi-arid Mountain West it was much less noticeable.

Update: Other AstraLite owners have made this same observation. Refer to comments below by John Vance and H. Hall.

The list of potential explanations is short. Either the down (which is not treated to be more water-resistant) has poor resistance to moisture, or the fabric breathability is low. Either way, this is a lovely product for semi-arid and arid climates, but not a great option for humid ones.

Especially in the footbox, the AstraLite performed poorly in consistently wet conditions. The bag was not exposed directly to moisture, but simply absorbed ambient humidity.


Sleeping quilts cannot be EN tested. And without this apples-to-apples rating, we’re unable to definitively answer the fundamental question when purchasing a sleeping bag or quilt, “What is the most thermally efficient bag with my required price point, dimensions, materials and construction, and company values?

Products specs can shed some insight, but it requires a deep dive into the details (e.g. loft, fill weight, length and width), none of which are independently verified and/or held to an industry standard.

The good news is that buyers have more choices — in both the number of brands and the number of excellent products — than ever before. If you do a little bit of homework (e.g. online reviews, and ideally in-person inspection), you’re almost guaranteed to be happy with your purchase.

Buy now: Western Mountaineering Astralite

Have questions about the AstraLite or NanoLite, or an experience with it? Leave a comment.

Disclosure. I strive to offer field-tested and trustworthy information, insights, and advice. I have no financial affiliations with or interests in any brands or products, and I do not publish sponsored content

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  1. Chip on June 13, 2019 at 2:10 pm

    What would you recommend or central united states?

    • Andrew Skurka on June 13, 2019 at 2:35 pm

      Define central. I think the key thing is that you’re not often camping in the clouds or getting days of rain and overcast, as you do in the Appalachians. You might be able to get away with it around the Great Lakes, which are drier and lower, and then definitely in the plains.

      • Chip on June 14, 2019 at 6:42 pm

        Arkansas, Tennessee, Missouri Eastern Oklahoma.

  2. Iván on June 13, 2019 at 3:01 pm

    What quilts would you recommend for a humid climate? Maybe a synthetic?

    Thank you for your insights!

  3. John on June 13, 2019 at 5:37 pm

    Do you think the wet weather performance was specific to this quilt, or a function of the down insulation generally? (Says the guy who lives in the PNW and is eyeing the REI Magma 30)… Thanks!

    • Andrew Skurka on June 13, 2019 at 6:42 pm

      All my demo quilts and bags are down (Sierra Designs) and they did much better than mine. Not sure if the shell fabrics are more breathable or if the water-resistant down was the difference. I doubt it was user error.

    • Andrew Skurka on June 14, 2019 at 2:33 am

      We had a lot of down bags and quilts on the trip. I don’t think anyone had synthetic, actually. And I was the only one who experienced problems. When my group did a mid-day reset dry, no other bag was as wet looking. And when I was drying out demo gear afterwards, no bag felt as wet as mine. The other down stuff had held up pretty well.

      Point is, I think this WM quilt seems especially vulnerable to moisture, and is not representative of other down products (including other WM products).

  4. Chad on June 14, 2019 at 8:08 am

    Hi Andrew,

    What is your experience when quilts with similar temperature ratings have drastically different fill weights? Notably I’ve consistently read that Western Mountaineering and Katabatic have very trustworthy temperature ratings yet with the “Astralite comparison” they have the lowest fill weights. I notice they also have a greater baffle height than the EE 30 which has more fill. I have been looking at the Nemo Siren due to availability and struggle to compare it to quilts on your list.

    • Andrew Skurka on June 14, 2019 at 9:50 am

      Apples-to-apples comparisons are really hard with quilts. That’s why the EN test is so wonderful — it scientifically demonstrates the thermal efficiency of each bag, per weight.

      With quilts there are so many variables to look at, and it’s difficult to know exactly how they are measuring each spec.

      • Steffen on June 15, 2019 at 7:37 am

        Maybe you quilt needs a gentle (hand) wash: through use dirt and body oils might have build up on both its fabrics and its down. If so, fabrics and down will attract water and condensation can easily transfer into the down.

        If you think your quilt has been extensively used, you could even consider to additionally re-proof it with an aftermarket DWR (e.g. Nikwax Down Proof).

        Less likely, your quilt’s down could have had too much of its natural fat and oil removed by WM’s down supplier, as “a certain amount of lipids are required for down and feathers to be resilient. Lipids on down and feathers help them resist water and also protect them.” (IDFL).

        • Andrew Skurka on June 15, 2019 at 11:47 pm

          The bag has been used for 30 nights, shouldn’t be a wear issue.

          And WM is a down pro, work directly with their farm. Unlikely that they screwed up the supply chain.

  5. Denver_Hiker on June 14, 2019 at 10:51 pm

    I got a wide quilt and am quite skinny. Am I missing some of the warming power of my quilt?
    It is Katabatic’s Wide version. I had originally thought since I toss and turn at night it would make sense but am having second thoughts.

  6. Hunter Hall on June 16, 2019 at 5:02 pm

    I’m taking the nanolite into the Yosemite high country July 1-7. I will report back. I expect it to be perfect.

    For three season use, I have the Z-Packs classic 20° Quilt/bag (with zipper) which honestly I’ve typically found to be a bit overkill for me, especially when wearing a jacket, etc.

  7. Dick Anderson on June 17, 2019 at 2:48 pm

    Yoke, not yolk. Sorry-I’m anal about proper spelling.

    • Andrew Skurka on July 1, 2019 at 10:04 pm

      Thank you. You’re always welcome to correct me — I get it as perfect as I can, but not always perfect.

  8. stephane on June 19, 2019 at 7:41 pm

    I own a WM apache and my wife owns a WM ultralight. Given the ”right” temperature, I systematically wake up with a wetter bag than my wife (and everybody else in the group). That is the reason I bought a synthetic quilt. I still wake up more damp than other with my quilt.

  9. Shae on July 30, 2019 at 9:28 pm

    Andrew, I just want some clarification. If you are sleeping in temperatures below 20F you go with a mummy bag? I’ve seen a lot of different views of cold weather camping and it’s getting me curious. Would one benefit more from getting a mummy bag (western mountaineering lynx) as opposed to a cold weather wuilt(Katabatic grenadier 5 degree) for mild winter conditions here in Colorado? Just want to here a experienced individuals point of view. Thank you sir

    • Andrew Skurka on July 31, 2019 at 6:31 pm

      As soon as temps are mostly below freezing, I go with a mummy. A quilt rated to, say, 5 degrees is stupid, IMHO. Its draftiness has huge consequences, and you need so much extra head insulation that there’s a huge fuss factor, and probably very little weight savings.

      As another CO guy, I find the two-bag combination of a 3-season quilt (that’s still light enough for peak summer temps) and a 10’s mummy (that’s ideal for late-fall and late-winter/early-spring, and okay in mild mid-winter temps) is about perfect.

      • Shae on July 31, 2019 at 8:28 pm

        Thanks so much Andrew. I’m a huge fan so I appreciate you taking the time to respond!

  10. H. Hall on August 7, 2019 at 4:45 pm

    I just got out of the High Sierra with the Nanolight and I had the exact same experience regarding the moisture. I actually took pictures where you can see droplets of water inside the quilt. The only source of moisture was me but I was sleeping under a tarp with a ground sheet and excellent ventilation so I’m a bit concerned/confused about it.

  11. Kody Aigner on September 4, 2019 at 8:59 am

    What are your thoughts on running a half quilt like the Nunatak 40 degree Nano Half Quilt with a high loft down hoodie? I see that this is popular among climbers but I see little mention of this idea among the ultralight crowd. Seems like it could be ideal for more restless but warmer sleepers during summer conditions in the mountain west, also perhaps allowing one to leave their mid layer at home.

    • Andrew Skurka on September 4, 2019 at 8:01 pm

      Never tried this.

      My hunch is that the weight benefit is negligible, because jackets are relatively inefficient insulators versus sleeping bags and quilts. It turns out that insulating rod-shaped objects like arms takes quite a bit of fabric given the volume of body being insulated.

      I suppose it’s more a matter of whether you think your insulated parka needs to be that warm when it’s used only as a parka. I’m not sure what the rationale is for climbers, maybe it’s because they tend to spend a lot of time on belay, generating no heat and therefore need to be very well insulated even when not in their sleeping bag. It’s the opposite for hikers — we move all day and can rely on body heat to stay warm, until we stop, and then we jump into our bag.

  12. John Vance on September 9, 2019 at 11:50 am

    I just returned from a 12 day trip in the Winds with the Astralite quilt and experienced similar moisture build up in the foot box. This was all internal moisture as the outer shell was not exposed to any moisture. I found that turning the quilt inside out was key to helping dry things out but I think that the “acrylic kiss coating” has greatly reduced the air permeability of the exterior shell to acquire greater moisture resistance from the outside.

    Oher than using a different shell material, I think if the footbox was shorter it would help mitigate this and make the quilt more comfortable as from the knees down it is fairly snug. I really like how effective the collar yolk worked even without using the neck snap. I also found the size of the quilt to work very well without having to use any straps at all. My hope is that the acrylic coating will degrade with time and I may have the back opening extended to make it more comfortable and limit the moisture build up to the last two baffles.

    • Andrew Skurka on September 10, 2019 at 3:21 pm

      I’m just really glad to hear that my experience with the condensation has been validated by other users. I wouldn’t expect to find design mistakes from a brand like WM, but I increasingly believe that their fabric selection was in error here.

  13. ben on September 13, 2019 at 10:11 am

    to pile on, i’ve used my astralite for ~20 nights, almost entirely in the sierra. it picks up more moisture than any other quilt i’ve used — though i notice it a bit more in the torso than the footbox. otherwise, i find it to be pretty near perfect.

  14. John Vance on September 16, 2019 at 9:29 am

    As I learn more about acrylic coatings, it may have been as much of a decision to go that route for easier handling of the 7d fabric during cutting and sewing as it was to add a bit of extra water resistance. The good news is that acrylic coatings, as a general rule, are not particularly durable. With it being a “kiss” coating – which is applied via a pick up roller and is a lighter coating that a direct to fabric application – I wonder if a couple of good washings might help degrade it and provide better breathability. A fabric sample would be nice to play with but I don’t think that will happen.

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