Western Mountaineering Bison Sleeping Bag: A God among Sleeping Bags

When you’re out in the wilderness, you’ll need to have some basic essentials with you, one of those being a proper sleeping bag. Unfortunately, many people opt for the cheapest sleeping bag, thinking that they’re all the same. But the fact is, they’re not.

Depending on when and where you’ll be camping or backpacking, it’ll greatly affect the sleeping bag you’ll be needing. Though, if you’re getting worried while reading this, don’t be. We chose the Western Mountaineering Bison Sleeping Bag as a great option for those who are in need of a heavy duty sleeping bag.

Product Specifications

  • Specifically designed for mountaineering
  • Lightweight
  • Highly compactable and durable
  • 850+ fill power down
  • Offset Insulated Double Draft Tubes and full down collar seal in the heat
  • V-Block Side baffles and horizontal baffles keep you down in place
  • Extremely well-built
  • Supports you in temperatures up to -40ºF

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If you’re a mountaineer, you’ll love this one. So, let’s get started by reviewing this sleeping bag and its competitors, that way, you’ll be able to figure out if this sleeping bag is the right one for you.


The Western Mountaineering Bison Sleeping Bag is a great bag for those who are into extreme outdoor activities. If you’ll be camping up in the mountains, a simple summer sleeping bag won’t cut it. When you’re facing the elements, you’re going to need a sleeping bag that’ll be able to support you. So, this sleeping bag is ideal for those who will be mountaineering and battling the elements of nature.

At the same time, it’s also relatively lightweight for a heavy duty sleeping bag which is another great feature about the Bison bag. Many people assume that the warmer the bag, the heavier it is but that’s not the case. The Bison sleeping bag is made of +850 fill power down which is a natural insulator that’s highly compressible. Let’s go into more detail about the Bison sleeping bag.


The Bison is a highly compactable sleeping bag which is another reason why it’s so popular. When backpacking, camping or hiking, you’re going to want a sleeping bag that’s easy to compress. Because it’s lightweight and compressible, packing it up makes it as easy as 1,2,3.

It comes with a stuff sack that you’ll be able to use and slip into your backpack without having to make extra room in your backpack. The stuff sack isn’t large enough to carry other items, however.

Design and Durability

This sleeping bag isn’t designed for those who are looking for something trendy with loads of extra gadgets attached to it. Instead, the Bison is designed with one thing in mind: keeping you warm. That being said, they designed the entire bag with that mindset, resulting in an exceptional sleeping bag for mountaineering. So, let’s look at the design of the Bison.

Aside from the 850+ fill power down, it’s made with large V-Block Side baffles and horizontal baffles across your chest that help keep the down in place. The double interlocking Draft Tubes and the down-filled Gore Windstopper collar seal both acts to seal in the heat, preventing any wind from seeping through the zipper teeth. The hood is also made of Gore Windstopper material, so you’ll be able to protect your head from the elements.

Its durability is guaranteed in the price. It’s not a cheap sleeping bag but it’s extremely well-built. If you’re going to be needing a sleeping bag for casual use, then perhaps you don’t need to invest in such a serious sleeping bag, especially if you’re just going to be using it for sleeping on the beach. However, if you’re a beginner or advanced mountaineer or hiker, then you’ll be wanting to invest in a sleeping bag that’ll guarantee you warmth and comfort.


If you’re going to be mountaineering, you know that you’re going to need a heavy duty bag. A bag that’ll be able to keep the cold out and the warmth in. What’s great about the Bison bag is that it’s designed specifically for mountaineering, this, it’s made with incredible durability and high-quality materials.

This sleeping bag is stuffed with 42 ounces of 850+ fill power down with an additional 10 inches of heat-trapping loft. In other words, not an ounce of warmth will escape this sleeping bag. The additional designs, such as the offset insulated double draft, full collar down, block side baffles and external hood ruff all help in ensuring that the heat stays in.

The Bison sleeping bag will be able to support you in temperatures as low as -40 degrees Fahrenheit. However, if you’re looking for a year-round sleeping bag, you might find yourself overheating in it during the summer. So, when it comes to summer and early fall use, this sleeping bag may be too much for you.


Nowadays, whether you’re going to be camping or mountaineering, most people are looking for a lightweight sleeping bag, which makes sense, as you want a sleeping bag that won’t weigh you down while carrying it. Now, though the Bison sleeping bag is for mountaineering, it’s lightweight.

In comparison to other activities, you should focus on having lightweight materials in your pack, including a sleeping bag. You probably thought that mountaineering sleeping bags are heavy, however, the Bison is not much heavier than your regular sleeping bag. Its total weight is 4 lbs 10 oz which is great for what you’ll be using it for.

The 850+ fill power down weighs only 42 ounces, so when you’re sleeping at night, you won’t feel extra pressure on your body. In terms of weight, the Bison really outdoes itself.


If you’re looking for a year-round sleeping bag, the Bison may be too much for you. You’ll’ be kept extremely warm during the winter, however, for summer, this sleeping bag will roast you. So in terms of year-round use, it’s not as versatile as other sleeping bags. Save your money and opt for something that isn’t so specialized.

When it comes to transportability, this sleeping bag is very versatile. You can easily stuff it into its pack and put it into your backpack without any problems. It’s highly compressible, so you won’t have any problems rolling it up. You’ll be able to use this sleeping bag in a tent, hammock, car – whatever the terrain, this sleeping bag will be able withstand the elements.

Unique features

Unfortunately, sleeping bags don’t come with special features like tents or hammocks. Instead of extra gadgets and add-ons, a sleeping bag’s unique features lie in its materials. However, there are some features of the Bison which are unique to Western Mountaineering.

Firstly, their products are built in the USA which nowadays is somewhat of a novelty. Having their products manufactured in the USA gives you a piece of mind that they’re built with quality and care. In addition, if there are any problems with the sleeping again it can easily be shipped for repair or replacement.

Another unique feature is the Gore Windstopper fabric which is a beautiful extra touch to ensure that the heat trapped inside your sleeping bag, stays inside. This fabric is highly durable and high-quality, so you won’t be seeing this in cheaper sleeping bags.

Value for money and guarantee

Sure, this sleeping bag isn’t cheap, but it’s not your regular sleeping bag. This sleeping bag is designed for people who are really needing secure shelter while up in the mountains. So for what it’s worth, the price tag matches the quality. Though, if this sleeping bag is out of your price range, we have some other options for you below.

In terms of the warranty, Western Mountaineering guarantees against manufacturer’s defects for an unlimited time. So, if there’s a problem, simply send it back to them and they’ll either repair or replace your sleeping bag at no cost to the owner. This is a standard customer guarantee considering what you pay for the Bison. Western Mountaineering is a company with a great reputation, so they treat their customers and products with great care.

Overall, when you look at value and guarantee, the Bison is really an all-in-one sleeping bag that you’d be crazy to turn down.

Close Competitors: Other products that you might like

Though we love the Bison sleeping bag, we want to show you other sleeping bags that you may be interested in. Though we love the Bison, we know that this doesn’t mean it’s the sleeping bag for you. So with that being said, we found some other amazing sleeping bags which may better suit your needs. Let’s take a look at the Bison’s competitors. .

Fjallraven Polar 30 Degree Sleeping bag

If you’re mountaineering or hiking, the Fjallraven Polar 30 Degree Sleeping Bag is another great sleeping bag that you could consider. This bag has been well-thought out for winter use. It’s padded with high-quality down for exceptional compressibility and insulation.

It’s built with box channels which assist in preventing any cold spots from occurring. What’s unique about this sleeping bag is the hood which was inspired by their jackets. The detachable synthetic fur edging around the hood helps minimize any heat loss. The hood gives extra movement in the head area that helps with the reduction of moisture by allowing air flow.

The zipper has a down-filled protective flap that prevents the air from seeping through the zipper’s teeth. If the zipper breaks while you’re on your trip, you have press buttons as a substitute to close the sleeping bag. It’s also lightweight, weighing less than 5 lbs, so you’ll be able to throw it into your backpack without having it weigh you down.

The Fjallraven Polar is stored in a large stuff sack that and can also be hanged via eyelets at the feet.

Western Mountaineering Puma Gore WS

If you’re a fan of Western Mountaineering, then you may want to try out the Puma Gore WS. It’s a great alternative if you’re still wanting to stick to Western Mountaineering. Made with Gore Windstopper, it’s highly breathable and weather resistant.

It comes with a roomy reverse differential hood to keep your head warm without having to cinch the hood tight. It’s made with +850 fill power down that gives the bag the warmth and comfort needed. In addition, the V-Block side baffles make sure that the down stay where it is without having it move around in your sleeping bag, creating cold spots.

Though it’s a mummy-style bag, it’s actually built with extra shoulder and foot girth, so you have extra room to add layers to your sleeping bag in case it gets cold. You’ll be able to sleep in this sleeping bag, enduring temperatures as low as -25 degrees Fahrenheit.

Though, if you’re looking for a lightweight sleeping bag, out of the ones we’ve reviewed, this is the heaviest one. The Puma Gore weighs 6 lbs which isn’t too heavy, however, if you’re wanting to shave off some pounds from your backpack, this may not be the best option for you. Though this sleeping bag is lower in price in comparison to the Bison, it’s still made with the same quality and durability.

Valandre Thor Sleeping bag

If you’re a fan of the Bison sleeping bag, however, are unable to afford its price, then this is a great alternative. The Valandre Thor Sleeping Bag is usually cheaper than the Bison. However, you still get a good quality sleeping bag if you’ll be mountaineering. It’s made of 100% nylon ripstop with DWR treatment and lined with 100% polyester.

The DWR treatment helps protect this sleeping bag from water, so you won’t have to worry about damaging the down. Though it’s not made with Gore Windstopper fabric, it still holds exceptional durability in comparison to other sleeping bags. It’s filled with 850+ fill goose down, so it’ll keep you cosy and warm.

The European Norm rating gives this bag a -2 degrees Fahrenheit, however, Valandre states that you’ll be able to use this well below zero. You’ll be able to use the static drawcord to cinch the hood together, protecting your head from the elements. It’s also designed with an interlocking draft tube so that no wind seeps through the zipper teeth.

This is the lightest bag out of the series we’ve reviewed. It weighs 3.7 lbs which is very lightweight for a sleeping bag, including ones that are not designed for mountaineering. So, if weight is a big issue for you, then this is a great option. Essentially, it’s built very similar to the Bison, minus some features such as Gore Windstopper fabric.


We’ve showed you the everything there is to know about the Bison bag and its competitors, but we’re not done. We know that nothing is perfect. Even though Western Mountaineering creates exceptional outdoor gear, of course, they’ll be something that people won’t like, that’s normal.

We don’t want to give you a biased review, so instead, we want to show you the advantages and disadvantages of the Western Mountaineering Bison.


  • High-quality design and construction
  • Very warm and lofty
  • USA made
  • Lightweight
  • Specific for mountaineering
  • Wide mummy-style
  • Gore Windstopper fabric


  • Above average price compared to a typical sleeping bag

The Bison sleeping bag is one of the best mountaineering bags on the market. It’s built with the highest-quality materials, ensuring that whoever uses it will be kept safe and warm.

Users of the Bison sleeping bag generally have not much to complain about, except the price. If that’s the only problem, that’s not that bad. It’s made with Gore Windstopper fabric that makes this sleeping bag literally impervious to the elements.

This sleeping bag is made with one thing in mind: keeping the cold out and the heat in.

Western Mountaineering Bison Sleeping Bag
  • Packaging
  • Design and Durability
  • Warmth
  • Weight
  • Versatility
  • Unique features
  • Value for money and guarantee


The Bison sleeping bag is one of the best mountaineering sleeping bags on the market. Made with Gore Windstopper fabric, it’ll battle the elements without you feeling an ounce of coldness. Made with 42 ounces of 850+ fill power down, you’ll be kept warm while the cold is kept out. It’s designed with a huge hood that’s also made with Gore Windstopper, keeping your head sealed away from the elements.

What makes this sleeping bag different from the others is the high-quality materials used to create this outstanding sleeping bag. But with that being said, it is more expensive than your average sleeping bag which may be an issue if you’re concerned about budget. However, with that in mind, if you’re going to be using it for mountaineering, this is well worth the investment.

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If you’re familiar with this sleeping bag, or another just like this one, why don’t you share your stories with us in the comments section below?


2 thoughts on “Western Mountaineering Bison Sleeping Bag: A God among Sleeping Bags”

  1. I have Puma Gore WS and it is my favorite sleeping bag so far. I bought one a couple of months ago and it is phenomenal. It is really durable and comfortable to sleep in. I am curious about Western Mountaineering Bison Sleeping Bag though because you have listed some awesome points.


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