There's very little moisture resistance on the bag itself but the down in the bag is a DriDown so it's treated with a waterproof barrier that repels water if it does get wet. One thing we may have to note is the sewn-through design of the Cloud 800. Most bags and quilts we've tested use some sort of continuous baffle design. Continuous baffles theoretically keep more of the down fill between you and the outside, while a sewn-through design adds more opportunities for your body to be pressed next to the thin shell fabric at the sewn seams. The shell material doesn't add much insulation from nighttime temperatures. Most bags and quilts we've tested opt for the continuous baffle design as a way to tweak the warmth of the bag, as the continuous baffles allow you to shake the down through different parts of the bag.

If you always wanted a lightweight, 800 fill down bag but never thought there would be an affordable one, here it is. If you share any of my frustrations with mummy bags the Cloud may help. If zipping together and snuggling with your tentmate is non-negotiable, well you can keep searching because this isn't your bag. Otherwise I give the Cloud an enthusiastic thumbs-up. Disclosure : Trailspace received a sample of this product from the brand for field testing and review. The product was assigned by Trailspace to this volunteer Review Corps member. I used this bag for the last four years on many multi-day treks and overnight hikes. I am an experienced hikers.As Rainey implied, nothing is perfect. My biggest gripe with the Cloud is that I cannot carry it when I go into the mountains with my wife. I’ll explain: Unlike all men and women’s REI sleeping bags, the Sierra Designs Cloud cannot zip together with your partner’s sleeping bag because, duh, it doesn’t have a zipper! My snuggle-loving wife says, “BOOO!” Sleeping bags do not generate heat; they only trap the heat we produce, so it is vital that you get into your bag when you are giving off warmth, don’t go to bed when you are cold, have a hot meal or a hot drink or do some brisk exercise to get you nicely warmed up. The Sierra Designs Cloud 800 35 features a generous pad sleeve to insert a sleeping pad in. To save weight, no down fill is located at the bottom of the bag where the pad sleeve fits.

Getting in and out of the bag is super easy since there's no zipper to fiddle with! I also found that the part of the bag that folds over you like a blanket stays nicely in place and is easy enough to throw off if you get too warm. Similar to any full zip mummy bag, the Cloud 800 can be very versatile, with just a little imagination. The zipperless design and footbox vent make it really easy to regulate temps - especially when things get warmer than you had planned. For unanticipated colder nights, you may opt to bundle up with an additional base layer, as the roomy comforter may make it a little harder to really keep things really sealed tight. At Valley and Peak we were particularly attracted to the Sierra Designs range of zipperless sleeping bags. For those who didn't want to make the jump from a sleeping bag to a Valley and Peak Quilt the Cloud 800 offers an excellent half way house. Plus the innovative features, like all Sierra Design products, bring great benefits to the user. Finally Sierra Designs has an excellent traceability policy, all products containing Down have a tag which can tell you where the Down came from and details on responsible sourcing are outlined in great detail. Because of the zipper-less design, the entry is a little tight. But once you've got your legs in the bag it works just fine. If you don’t want the restriction imposed by a zipped bag and don’t fancy a quilt because you move around too much at night then the Cloud 800 bags deliver unrestricted rest when you want it and warmth when you need it.

There’s nothing else on the market that uses the ‘zipperless bag’ approach of the Cloud 800 – though Big Agnes’ Sidewinder SL20 is another bag specifically designed with side sleepers in mind.