Review: Sierra Designs Cloud 35 & 20 || Premium mummy/quilt hybrid

A cowboy camp with the Sierra Designs Cloud 35 in upper Cascade Creek on the Pfiffner Traverse.

For eight consecutive nights in July, I slept in the Sierra Designs Cloud, which is new for spring 2018 and which may establish a new sleeping bag category. SD describes it as a “zipperless mummy,” but it takes just as many design cues from top bags and quilts.

Review: Sierra Designs Cloud Sleeping Bag

I can think of at least three audiences for the Cloud:

1. An existing mummy bag sleeper who finds it overly restrictive, who rolls off their pad at night, and/or who are annoyed by snagging zippers.

When closed up, the performance of the Cloud is on par with a conventional mummy.

2. A new backpacker who want a lightweight sleeping bag with premium materials that is priced lower than comparable models from the likes of Marmot, Mountain Hardware, and Sea to Summit. And,

3. An existing quilt user who wants a less drafty bag for colder temperatures, but who fears being confined in a mummy after enjoying the freedom of a quilt. Personally, I’m in this camp.

But its versatility and variable girth are more quilt-like.

The Cloud features 800-fill power water-resistant DriDown and 15d shell fabrics. It is most suitable for backpacking, when warmth-per-weight is a paramount concern. For camping, comfort and cost can be prioritized ahead of weight. It will be available in two versions:

Each version is available in two lengths: regular (up to 6-foot) and long (up to 6’6″; +$20).

The 20-degree will also be available as a women’s bag (1 lb 12 oz, $300), fitting up to 5’8″. It includes the same fill weight as the unisex 20-degree regular (14.8 oz), but since it’s proportionally smaller it should be a few degrees warmer; extra down was allocated to the footbox and top core. An EN test was not done for this version, as an expensive-saving measure.


The Cloud originated with SD’s admission that it’s innovative Backcountry Bed can not compete with traditional mummies or quilts on a warmth-per-weight basis, all things being equal (like fill power, shell fabrics, and sizing). It simply requires too much build, like overlapping panels, extra seams, and a pad sleeve.

The Cloud, however, can and does. The 35- and 20-degree versions are each just 1 oz heavier than the new Nitro bags, which are pure vanilla mummies that feature the same materials and sizing.

Zipperless mummy

The Cloud differs from a conventional mummy (e.g. the Nitro) in two respects. First, it has no zipper. Instead, the top of the Cloud from the waist to the shoulders is more like a comforter or quilt, detached from the bag’s side on sleeper’s left. Despite this zipperless opening, drafts should be minimal or non-existent: the comforter hooks around the shoulder, and it overlaps with the side insulation when the sleeper is laying down.

The top comforter tucks into the side of the bag and has a shoulder “hook” to eliminate drafts even without a zipper.

Second, the Cloud is technically a top bag: it features a sleeve on its backside, into which a sleeping pad should be inserted. From the waist to the shoulders, the Cloud has no insulation on its underside, instead relying on the insulating value of the sleeping pad.

The weight consequences of these design differences are mostly a wash. By eliminating the zipper and underside insulation and baffling, the Cloud drops weight. But the overlapping materials and pad sleeve add it right back.

Gram weenies may wonder if the pad sleeve is critical. It’s not, but I’d leave it alone — I think it’s advantages are worth an extra ounce. The pad sleeve prevents the user from rolling off the pad, and allows the user to rotate within the bag. And in the particular case of the Cloud, the sleeve keeps tension on the bag’s top side, helping keep open the hole.

The pad sleeve adds about an ounce of weight, but improves the tension on the comforter and prevents the user from rolling off the pad.

Variable girth and sizing

Versus a traditional mummy, the Cloud is less restrictive and it lacks a snag-prone zipper. It has one more advantage, too: variable girth, due to the overlap between its comforter and sides.

This feature is most meaningful to backpackers who supplement the warmth of their sleeping bag by wearing their hiking clothes at night. For example, the Cloud fit me perfectly on warm nights, when I slept in just my hiking shirt and underwear. But it remained a perfect fit on cooler nights, when I also wore my insulated jacket (and later removed it because I was too warm).

I’m 6-feet tall, weigh in the upper 150’s, and have a 40-inch chest. The regular-sized Cloud offered sufficient height and more than enough width.

Temperature rating

The 35- and 20-degree versions have both been EN-tested. Your nighttime comfort may not coincide perfectly with the EN test (thankfully, mine does), but at least it gives you apples-to-apples comparison data between sleeping bags.

During my July trip — on which I used a drafty open-sided tarp — nighttime temperatures were typically in the 40’s. I found the 35-degree bag amply warm. If I had sealed it up while wearing my hiking shirt, shorts, pants, lightweight fleece, and puffy jacket, I’m certain that I could have been comfortable with temperatures in the 20’s.

Room for improvement

My single criticism of the Cloud is the side-sleeping experience. In this position, my face was directed at the side of the bag, whereas a traditional mummy bag would have rolled with me. This problem is inherent with top bags, and was remedied easily enough — I tucked the side or top of the Cloud under my face.

Thankfully, I’m generally a back sleeper, so the Cloud worked for me. And it’s not as if mummies aren’t also flawed — active sleepers can roll completely off their pads or become utterly twisted inside of the bag.

Posted in , on September 14, 2017


  1. Jay on September 14, 2017 at 5:45 pm

    Really interesting bag. Love the design generally. The thing I think would give me a hard time is the fact that it only opens down to your waist, leaving no way to vent below that. I’m a hot sleeper and I live in Arizona, and I use the winters to enjoy the splendors of the desert and generally stay out of the high country then.

    The bigger upshot for me is that SD has been heavily discounting the Zissou bags, and I just picked up a 30 degree Zissou at a great price for Arizona winters when my warm-season 50 degree quilt just won’t cut it anymore.

    • Makerlight on April 15, 2018 at 6:07 pm

      If you are looking to vent below the waist then the Cloud 800 does have a solution that Andrew may have not mentioned. The footbox has an opening at about where your calves would be, facing your sleeping pad. It allows you to slip out your feet when they get too hot, without using your hands or fiddling around. When it gets a bit drafty then slide your feet back inside the bag. The opening overlaps so that no cold gets in as well. A good feature for sure.

  2. Rene on September 14, 2017 at 8:04 pm

    Andrew, your cowboy camp looks like such a mess for how I thought you’d want camp to look like…neat and tidy but I’m most likely wrong. Also, I almost cried when I heard you’re seriously contemplating not continuing with the ultrarunning races even though you’re clearly still a stud…please give UTMB another shot and double down! As always, I love the content and appreciate it. Take care.

  3. David Wiese on September 15, 2017 at 11:28 am

    Hey Andrew,

    When you use a mylar/emergency blanket as your groundsheet, do you always put the reflective side down like in the pictures? Or are there cases where you will turn it over?


    • Andrew Skurka on September 15, 2017 at 11:51 am

      I don’t think it matters.

  4. Karen on September 16, 2017 at 8:14 pm

    Thank you for the review. It’s something to consider as I am always off my pad!

  5. Brenden Woolley on October 3, 2017 at 9:22 am

    Andrew, does the footbox have a self sealing foot vent/hole like the backcountry beds do? That would allow heat venting and adjusting for when you need to cool your lower half down. I really liked that in the backcountry beds, it worked well.

    • Andrew Skurka on October 3, 2017 at 10:04 am

      Yes, it does.

  6. juan on October 21, 2017 at 6:22 am

    Those colors are awful

  7. Robert on November 17, 2017 at 10:09 pm

    How would you rate this bag for stomach sleepers and people who move alot
    I have 5 Montbell bags

    • Andrew Skurka on November 18, 2017 at 2:04 pm

      I’m a back sleeper and don’t move around a lot, so I can only speculate.

      The pad sleeve will help, because it locks the bag onto the pad in a correct position. You can move around inside of it without getting twisted.

      The half-comforter is better than a normal lightweight mummy (which will have a half-length side zip), but it’s not as good as the SD Backcountry Bed. The Cloud is about the same weight as the mummy, but quite a bit lighter than the BCB, especially the 2018 models because they’ve been redesigned for comfort and cost, not high performance.

    • Andrew Skurka on December 6, 2017 at 2:21 pm

      I have not slept in an EE bag and I’ve had few clients with them. I think they are highly regarded, although I think the consensus is that their temperature ratings are aggressive.

      A quilt and the Cloud are pretty different products. Given the temperature ratings you are looking at, I would push you to the Cloud. Once nighttime temps are reliably below freezing, I always take a mummy bag, because quilts are too drafty and leave the head too exposed. And when you start looking at how a quilt addresses those problems (e.g. lashing system to the pad, insulated balaclava) I just assume have a simpler mummy.

      As far as the Cloud vs a traditional mummy like the Nitro, I prefer the Cloud. The top-bag aspect is nice (you can roll inside the bag without getting twisted and without rolling off your pad), but the comforter makes it less restrictive than a mummy.

  8. Aaron Fisher on December 7, 2017 at 6:19 am

    I’ve used a Big Agnes bag with the same style of sleeping pad sleeve. It works great with a rectangular pad but turned out to be drafty with a narrower, tapered pad. Have you tested this with a tapered pad? Any issues? I will add that I was in zero degree temps and the draft was very unwelcome. Thanks!

    • Andrew Skurka on December 7, 2017 at 7:43 am

      I used it with a regular length 20-inch NeoAir XLite. It was fine, no noticeable drafts.

      I don’t think a 25-inch pad works with the cloud.

      • Rob on December 7, 2017 at 7:32 pm

        Just checked on SD’s website; the long version will take a 25″ pad.

        With the opening on the left side, how would it be for right side sleepers?

        • Andrew Skurka on December 11, 2017 at 9:55 am

          The 25-in width on the Long makes sense.

          I’m a back and right-side sleeper, too. When sleeping on the right side, I simply tucked the hood under my face, so that I wasn’t breathing directly into fabric. You can tuck only part of the hood under, so that the top of your head still stays insulated. All that said, if you were pushing the warmth limit of the bag each night and really needed it to be sealed up, this would be a shortcoming of the Cloud, assuming that you keep it strapped to the pad (which you don’t have to — it just works better that way).

  9. Mer on March 4, 2018 at 2:38 pm

    Hey Andrew,

    Torn between the women’s Cloud and Backcountry Bed 20 700 DriDown – was leaning towards the seemingly less restrictive backcountry bed but the lower weight/warmer rating of the cloud is tempting (back/side sleeper). Input/advice appreciated!

    • Andrew Skurka on March 5, 2018 at 7:54 am

      The weight of the BCB makes it prohibitive for any serious backpacking. Car camping or leisure backpacking, fine, but if you ever want to cover miles, you’ll always know it’s an anchor.

  10. Keith on March 6, 2018 at 2:58 pm

    Hi Andrew. Is it fair to say this is your current go-to recommendation? I am planning to section hike the GDT over the next few years and have been completely overhauling my kit. I purchased a Flex Capacitor (which I love) and am about to pull the trigger on a duomid with solomid XL inner (I chose the duo for trips when my daughter is along).

    My next big purchase will be a sleeping bag. Current contenders are the MLD Spirit Quilt & E.E. Revelation quilt. Basically I’m looking for one bag to cover most conditions, weight of around 1.5lbs, and want the most bag for my buck. The E.E. Quilt is at the upper end of my budget.

    Thanks once again for your time.

    • Andrew Skurka on March 7, 2018 at 9:10 am

      Go-to recommendation? Hmm, I don’t know if I’d go that far, mostly because I think context is important before recommending ANY product.

      For your purposes I would stay away from synthetic insulation: you’ll be in very arid environments and using it for multiple years, so stick with the insulation that is more thermally efficient and that has better long-term performance. Among your choices, that would limit you to the EE and SD, but I’m sure if you looked more you’d find other similar options.

      I would not hesitate in using the Cloud as my only bag. It’s EN tested, light, and very reasonably priced. I think this is more of a preference issue: Are you okay with the relatively restrictive design of the Cloud in exchange for better draft protection and a much cleaner system to keep you on top of your pad? If so, then I think it’d be a good choice.

  11. Keith on March 7, 2018 at 9:42 am

    Thanks Andrew. I wonder if there’s some confusion. I’m talking about the Great Divide Trail up here in Canada. I’ve been told to expect intense bug pressure and “more rain than you’d expect”, hence my inclination toward synthetic.

    • Andrew Skurka on March 7, 2018 at 9:45 am

      Sorry, I read GDT and spaced out thinking Grand Enchantment.

      The GDT is still well within the bounds of down. It’s not the BC coast or the southern Appalachians. All that you need is 30 minutes of sunshine every 3 or 4 days and you’re good to go.

  12. Keith on March 7, 2018 at 10:31 am

    Thanks so much Andrew!

    Always appreciate the intel.

  13. Seb on April 22, 2018 at 6:25 pm

    How do you deal with pulling a bivi bag over this arrangement between the bag and the mat?
    Equally, don’t you find that the need to use a bivi can negate the liberating nature of a quilt?

    • Andrew Skurka on April 22, 2018 at 7:55 pm

      I didn’t use the Cloud with a bivy. I think bivies are best with quilts, because they offset the inherent draftiness of that product. In the Cloud, you don’t have a draft problem. And I didn’t encounter bugs on any of the trips for which I used the Cloud, so I didn’t need a bivy or inner for that reason, either.

      So long as the bivy has adequate girth, it does not interfere with the flexibility of the quilt.

  14. Patrick Moore on May 21, 2018 at 3:54 pm

    Curious about a couple things. I’m just under 5 foot 8 and weigh 160llb. Do you think a woman’s bag would be an option? Same fill weight but 4in shorter would correlate to a little more warmth.

    Second, my Big Agnes Q core pad is 4 and 1/2 in thick, is that too thick to to be able to use with the sleeve with the bag?

    • Andrew Skurka on May 22, 2018 at 8:11 am

      Customer service should have good answers to both of these questions.

      You should be aware that the women’s bag has the same amount of fill as the men’s bags, but the women’s bags are smaller. That means more fill distributed into fewer baffles = warmer.

  15. Albert on May 24, 2018 at 12:45 am

    Thanks for the review Andrew,

    I’m 6’3 and slim built, would a regular cut it or were you at it’s limits at 6 foot?


    • Andrew Skurka on May 24, 2018 at 8:47 am

      The regular was okay for me (at 6′ and slim) but for 6’3″ I think you’d want the long. There are few things more annoying than being jammed vertically into your sleeping bag.

  16. Eric on June 8, 2018 at 3:18 pm

    I have backpacked a fair bit, and am inspired to try out some nights of cowboy camping BUT have a mental phobia about cowboy camping in bear country. Here in Alaska a tent provides a bit of a psychological barrier. What are your experiences and recommendations for cowboy camping in Southcentral Alaska, or bear country in general?

    • Andrew Skurka on June 12, 2018 at 3:04 pm

      I’m glad to hear you describe it as a psychological barrier, because that’s all it is. Some sil-nylon is not going to stop a bear if he wanted what’s inside. I do wonder, however, if the shelter gives them pause, i.e. “WTF is that thing? Maybe I should get out of here, even if it smells like chocolate.”

      FWIW, I rarely cowboy-camped in AK. I liked being able to close out the world — it’s a mentally challenging place to backpack, especially solo. Also, there always seemed to be bugs or a risk of weather.

  17. Mike on August 29, 2018 at 3:25 pm

    Andrew, I prefer to sleep in the open as much as possible, and choose dry-down fill for that reason, but the potential for water running directly into this bag, where the quilt top tucks inside, is a little concerning to me. Thoughts?

  18. Mike G. on August 29, 2018 at 3:44 pm

    Do you know if there are plans to add a hook and loop closure to keep the quilt secured in place? I believe AS added this feature to the BCB.

  19. Boyan on September 12, 2018 at 2:17 am

    In the market for a 15-20F shelter. As an anal retentive type, I started making a spreadsheet of the specs of the various “recommended” options. If there is one thing I hate about mummies it is not being able to separate my legs, specifically if the temps are around freezing. Noticed that the “standard” girth for mummies is 59″ at shoulders and 38″ at the feet. Hence the Nitro looked very attractive, with a full extra 4 inches of shoulder and foot girth, not to mention the footbox venting option. Just when I had made up my mind to go for the Nitro I come across this post. What gives me pause is that the girth spec of the Cloud is a more traditional 60/40 rather than the roomier 64/42 of the Nitro. It seems that the girth spec of the cloud, given its design, is somewhat of a meaningless number, since it can be as wide as you want it to be. Is this correct?

    As a side point, all bags I currently own have a full zipper. When the conditions are warmer relative to the bag’s rating I use it like a quilt – open up the zipper, stick my feet into the lower section. This gives me quilt-like functionality with the option to go full mummy when the conditions require it. It is a pitty that in the last few years most down mummy designs have gone to half zip. My MH Phantom 0 from 7-8 years ago has a full zip.

  20. Greg Stein on November 28, 2018 at 4:22 pm

    Andrew, I’m planning a family trip to Iceland in Summer 2019 (July-August). We will be hiking the famous Laugavegur trail and Firmvortuhals trail (god knows how to pronounciate this). Would you recommend this bag in 20-degree version for the conditions of Iceland? We will be sleeping in a ZPacks Duplex and Triplex tents (we are 6 people). I’m planning to bring my EE 20F quilt. But I’m really not sure since all I read online about conditions there seems scary 🙂
    Oh, and the kids are rather small 5, 10 and 13 y.o.

    Thank you!!

    • Andrew Skurka on November 28, 2018 at 4:26 pm

      I’d go with the lighter version, and I generally run cold. You have lots of people in your shelters, and you’re there at the warmest time of year. The only reason to get the 20-deg is if you’ll get more use out of that version on other trips.

      • Gregory Stein on December 1, 2018 at 10:53 pm

        Andrew, thank you for your input! We will definitely use it on other trips. I was thinking that the fact it is a “zipperless” bag and no bottom insulation may cause drafts (we all use NeoAirs Xlite) and hence the actual temp rating of the bag is lower (i.e. for higher temps).

  21. Makerlight on December 3, 2018 at 6:49 am

    I’ve been following this thread for a while now trying to get insight into peoples experience with this bag. I move a lot at night and I don’t like zippers, but I do like “light and compact” gear. Yesterday while waking around MEC (Canada’s version of REI) i saw the cloud 20
    On display. It was one of only 2 in their entire cross country inventory, so after a quick demo I bought it since Sierra Designs doesn’t ship this model to Canada.
    I brought it home to test in a relatively cold bedroom above the garage. I inflated my Nemo Tensor R mattress and S to S premium pillow to see how comfy the whole system would be. Within a couple minutes I accidentally fell asleep! My wife came in and woke me.
    I’m not sure how well it does in cold weather but I can attest to it’s comfiness after this test. You definitely feel like you are well wrapped in a cloud and not like a coffin with some of my other mummies.

    • Andrew Skurka on December 3, 2018 at 7:49 am

      These bags are EN-tested, so you can be assured that the temp ratings are consistent with industry standards. Exactly how you relate to industry standards is another issue.

  22. Luciano on January 23, 2020 at 4:18 pm

    Live in Sweden and looking for a bag that will take me through a few nights wintertime with temperatures around 0 -5 celcius (32F to around 20F). The bag will be used mostly during spring/summer/autumn. Not really sure if to go with the 20 or the 35 version. Don’t mind sleeping with clothes on a few nights if tempereatures drops if I would get the 35F version. Was also thinking if going out when really could always also bring a quilt.

    Thank you!

    • Gregory Stein on January 25, 2020 at 4:10 pm

      Definitely take 20F version. After using 5 of these in Iceland in summer (went to the far north Hornstrandir) we were sleeping sometimes with clothes on. The issue is the drafts that come from that hole under your back. I think it was sick decision to use Neo Air xlite pads with these bags. You’d be much better with rectangular shape pad.

  23. J. Brandon on September 12, 2020 at 12:54 pm

    Just purchased the cloud 20. I have only tried it out with neo air in the living room. The sleeve is really big (I have the long), too big. I would want to modify this feature.
    Would you pair this with a 30-40 degree down or synthetic quilt for 0 (Or below) degree temperatures? What about adding a bivy? Thanks

  24. Mark Woods on March 5, 2021 at 11:29 am

    Interesting concept. Along those lines (a company trying something different), have you tested out Montbell’s Seamless Hugger bags? I’ve been using a Katabatic quilt but am (hopefully) heading into some sub-freezing temps later this year and want to get a bag. Intrigued by the Montbell. Would like to know your thoughts (also would love to know what you’d say about the shell choice: 7D Ballistic Airlight or 13D Gore-Tex Infinium Windstopper).

    • Andrew Skurka on March 5, 2021 at 11:58 am

      I’ve not tried that model from Montbell, but it’s been around a long time and they strike me as a brand that generally understands insulation.

      FWIW, if nighttime temps are regularly below freezing, I switch to a mummy bag without exceptions. In those kinds of temps, there just isn’t enough insulation around your head if you’re in a quilt. And while you can add insulation systems (e.g. insulated balaclava) to a quilt, they just seem way fussier and less efficient than a mummy.

      • Mark Woods on March 5, 2021 at 12:40 pm

        Thanks. Makes sense. I was tempted to try to make my Katabatic quilt work, but was thinking that at some point it’s better to go the mummy bag route. Any thoughts on 7D for a bag shell? I know that’s fairly minimalist, but I see that several respected companies use that in their UL options.

        • Andrew Skurka on March 5, 2021 at 12:53 pm

          Fabrics are not created equal, even 7d vs another 7d. But Montbell is quality and I don’t think you need to worry about them using a cheap/crappy 7d fabric.

          Sleeping bags don’t take much abuse, so it’s one item that you can keep light. I wouldn’t necessarily say that about shelters, and certainly not backpacks or clothing.

          • Mark Woods on March 5, 2021 at 1:28 pm

            Thanks, Andrew. Really appreciate all your insight and expertise (on your site, in your book and beyond). Hoping to do one of your trips one of these years.

  25. Dan on May 4, 2024 at 3:18 pm

    I was pretty happy with my Cloud 35 up until recently, when the fabric started letting down and feathers through, especially around the stitching. And I’m not even gonna mention in how many spots I already had to fix that stitching.

    It hasn’t been that long since I bought it, about 6 years, and I don’t think I used it more than 100 nights in this period. Plus, I tend to take good care of my gear, especially anything that is filled with down.

    Too bad, I really enjoyed the design, but now I think I will just buy a WM, and hopefully this will be the last summer sleeping bag I ever buy.

    Writing this comment because your review here was pretty much the reason why I bought the Cloud.

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