Reviews You Can Rely On

Big Agnes Storm King 0 Review

An integrated pad system and a wide cut make this bag a great choice for those who feel constrained in a mummy-style bag
Big Agnes Storm King 0
Photo: Big Agnes
  • 1
  • 2
  • 3
  • 4
  • 5
Price:  $350 List
Pros:  Comfortable, wide, unique pad sleeve
Cons:  Poor warmth-to-weight ratio
Manufacturer:   Big Agnes
By Matt Bento ⋅ Senior Review Editor  ⋅  Apr 13, 2017
  • Share this article:
Our Editors independently research, test, and rate the best products. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Learn more

Our Verdict

Big Agnes discontinued the Storm King in 2019.

The Big Agnes Storm King 0 is unique to this category due to its wide cut, spacious hood, and pad integration system. With so much room to toss, turn, and sprawl, our testers found it mega comfy, but there was great division over the pad integration, and the Nemo Sonic ultimately won the Top Pick for Comfort Award. The Storm King is one of the heavier bags in our selection, but for night after night, bed-like comfort, the Storm King is a great option.

Our Analysis and Test Results

This bag is all about comfort. If you're a finicky sleepier or you've grown tired of constraining mummy style bags, the Storm King may be a good option. We found it wasn't as warm as similarly rated bags like the Western Mountaineering Antelope, but if you've decided you can't get good nights rest in a sleeping bag, it might be time to hop into the Storm King.

Performance Comparison

This bag relies on a sleeping pad stuffed into a special sleeve to...
This bag relies on a sleeping pad stuffed into a special sleeve to insulate the bottom, saving a few extra ounces of fill weight.
Photo: Jenni Snead


Like the Big Agnes Crosho, the Storm King employs long, vertical baffles to keep the down from shifting around and creating cold spots. We feel this design works well, but the Storm King only has 24.5oz of 650 fill power down, compared to the Crosho's 35 oz of 850 fill power down, making the Crosho significantly warmer. A fairer comparison would be the Rab Ascent 900, which has the same "0-degree" rating as the Storm King, but has 7.2oz more of the same fill power down, and a 10oz lighter materials weight. Our testers feel that the Storm King is a touch warmer than the Nemo Sonic and the super light Western Mountaineering Versalite.


The Storm King 0 weighs in at 3 lbs 7.5 oz, making it 2 oz heavier than its close competitor, the Rab Ascent 900, and 10 oz lighter than the Kelty Cosmic Down 0. Since this bag is filled with 650 fill power down, it requires more of it to achieve the warmth of lighter bags with higher quality down but also keeps the price down. The Storm King's large cut that makes it so comfortable also adds to the overall weight of the bag.

The pad integration system cuts down the actual bag weight because there is no down on the underside of the bag. The design relies on the inflated sleeping pad that inserts into a sleeve on the bottom of the bag to insulate the back of the bag. Since you will most definitely need to carry a sleeping pad on cold weather overnight adventures anyway, we did not consider the weight of the sleeping pad when evaluating the overall weight of the Storm King. That being said, we used the Big Agnes Q-Core XLS Pad (sold separately) while reviewing this bag - it weighs 15oz.

The lighter colored interior fabric caused this bag to dry out...
The lighter colored interior fabric caused this bag to dry out slower than bags with a dark interior like the Western Mountaineering Antelope.
Photo: Jenni Snead


The wide cut and excellent fitting hood of the Storm King go a long way to make it a comfortable bag. There is plenty of room in this bag to accommodate most sleeping positions. The pad integration system was a hot topic of debate among our testers and was ultimately the reason this bag narrowly lost to the Nemo Sonic 0 for our Top Pick Award for Comfort. Some of our testers felt that the pad integration sleeve is great. It kept them on the pad through the night and held the bag in place while they shifted around inside. Others hated that they couldn't roll the whole bag onto its side, or sit up easily while still in the bag.

With 24oz of 650 fill power down, this bag is quite packable.
With 24oz of 650 fill power down, this bag is quite packable.
Photo: Jenni Snead

Packed Size

This bag stuffs down slightly smaller than the Rab Ascent 900 and significantly smaller than the Kelty Cosmic Down 0. It also compresses to a smaller size than warmer bags like the Marmot Col and The North Face Inferno -20. It Isn't as compact as the Western Mountaineering Antelope MF, or the Nemo Sonic. The REI Co-Op Magma 10 packs down smaller than any other bag in this review, but isn't quite as warm as the Storm King.


The main unique feature of the Storm King is its integrated pad sleeve. Take it or leave it, the pad integration makes it feel a lot different than the other bags. The thinking behind this design is that since your weight is compressing the insulation underneath you, and the pad is what is actually keeping you insulated from the ground. This feature works well, but you have to use it, meaning that if you don't stuff the pad in the sleeve, you risk exposing your uninsulated back to the elements when you roll over. The lofty draft collar is well positioned, but it doesn't have its own cinch cord. The full-length draft tube does a good job keeping out cold air from the zipper. The head end of the pad sleeve is stretchy so you can stuff a jacket or a small pillow in there, for a comfortable headrest that stays put all night.

We were happy to see puddles collecting on the outside of the bag...
We were happy to see puddles collecting on the outside of the bag and not the inside. This bag didn't soak through in our light rain testing.
Photo: Jenni Snead

Weather Resistance

The Storm King features down with a hydrophobic treatment. This may help the bag dry faster and retain more of its loft, but time after time in our testing, we found that the shell fabric was the most important factor when keeping the bag warm and dry. Water beaded up on the polyester ripstop microfiber shell and shed easily, never soaking through the stitching, keeping our testers dry in the light rain tests. In the submersion testing, it took in more water than the Rab Ascent 900, but not as much as the Kelty Cosmic Down 0. In the real world, this bag does fine in snowy conditions as long as you're equipped with a decent tent or bivy sack, but it doesn't stand alone against the elements as well as the Marmot Col or the Feathered Friends Snowbunting.

Photo: Jenni Snead

Best Applications

If you're interested in a comfortable bag and think you'll dig the integrated pad system, then this bag would be suitable for shorter winter backpacking trips. In a car camping scenario where weight is not a concern, the Storm King offers superb comfort. It would be excellent for a winter road trip to Bishop or Joshua Tree, where warm sunny days give way to chilly nights.


At $349.95, the Storm King is in the same price range as the Rab Ascent 900. However, it is not as light, warm or as weather resistant as the Rab contender. The Storm King works best with a Big Agnes pad sized 20x72 to fit the sleeve. This adds $139.95 if you get the Q-Core XLS insulated pad, making the complete sleep system $489.90. Of course, all bags we reviewed perform significantly better with a sleeping pad, so you'll almost surely need one anyhow.


The Big Agnes Storm King 0 is a good option if you're a finicky sleeper who can't get a comfortable night's sleep in a traditional mummy bag. There is loads of room in this bag, and if you like the pad integration system, this could be a solution for quality slumber before a big day of adventure. If you're looking for equal comfort in a lighter, more compressible bag, check out the Nemo Sonic, our Top Pick for Comfort.

Matt Bento