Home > Camping > Sleeping Bags/Pads

Marmot Col -20-Degree Review: Cozy Sleeping Bag Fit for Alaskan Peaks

Sleeping in marmo col -20 bag inside tent(Photo/Christian Black)
Support us! GearJunkie may earn a small commission from affiliate links in this article. Learn More

I tested the new Marmot Col -20-Degree sleeping bag in true expedition conditions over 35 days in the Alaska Range.

My trip encompassed a personal climbing trip out to Mt. Huntington in pursuit of some technical objectives at lower elevations. I followed this with a 25-day patrol with the Denali Climbing Rangers of the West Buttress route on Denali. This was as a volunteer for the Denali Rescue Volunteers program.

These adventures culminated in the perfect trip to put the Marmot Col -20-Degree sleeping bag through the wringer for over a month straight in an appropriate setting.

In short: The Marmot Col -20-Degree proved worthy of the conditions in Alaska’s high ranges. It provided appropriate warmth with comfort not usually found in this category of sleeping bags. And the substantial roominess and feature set added to livability in expedition settings.

Marmot Col -20-Degree Review: The Perfect Trip

Marmot Col -20° Sleeping Bag on an Alaskan glacier
(Photo/Christian Black)

For the first part of our trip, two friends and I flew into the east fork of the Tokositna Glacier. We set up a base camp for 10 days at the bottom of the west face of Mt. Huntington.

Less-than-ideal weather allowed us only two attempted climbing outings. We spent many days in base camp. I was often cuddled up in the Marmot Col -20-Degree sleeping bag late into the mornings.

For the second part of the trip, I geared up with the Denali Climbing Rangers. I accompanied them on a 25-day West Buttress search-and-rescue patrol. This foray was part of the Denali Rescue Volunteers program.

We spent about a week making our way up from base camp to the 14,000-foot camp and spent 10 days acclimatizing there. After adjusting to the altitude, we pushed to a 17,000-foot camp. We quickly moved on to a successful summit day thanks to the splitter weather during this spring Denali season.

I had the chance to use the Marmot Col -20-Degree for all 10 days on Mt. Huntington and 25 days on the patrol and was pleasantly surprised with its comfort and warmth. Below are my thoughts after spending roughly 35 nights total sleeping in the Marmot Col -20-Degree.

Specs and Features

Marmot Col -20 open on snow
The cozy interior of the Marmot Col -20-Degree; (photo/Christian Black)

The Marmot Col -20-Degree sleeping bag is an 800-fill-power down bag with a waterproof and windproof Pertex Shield as the outer fabric. Weighing in at 4 pounds 7.3 ounces, the Marmot Col isn’t the lightest bag for the temperature range. But its comfort and useful features improved the overall livability. This bag is built with expeditions in mind. It provided a warm, safe haven to retreat to after endless days on the glacier.

With the Regular size coming in at 83 inches in length and a shoulder circumference of 64 inches, the Marmot Col was spacious. It comfortably accommodated me, plus any gear or layers I wanted to keep warm. A generous cinch collar around the neck and large draft tubes guarded all zippers, which ensured a cozy seal that kept warmth in.

Marmot Col -20° Sleeping Bag main zipper
The main center zipper of the Marmot Col -20-Degree; (photo/Christian Black)

The beefy center zip was one of the smoothest zippers I’ve ever used, almost never snagging. It allowed easy entry and exit into the bag.

Two additional zippered arm/vent holes let me wear the bag while bivying or as a way to vent the bag if it got too warm. One gripe about these two arm/vent zippers is that there was no way to access the zipper from the inside. The zipper pulls are only on the outside — to vent the bag, I had to undo the main zipper and reach around the outside of the bag. A bit of a disappointing design on an otherwise useful feature.

The Col also has a few interior pockets for smaller items. A small zippered pocket near the neck housed my headphones, earplugs, and a sleep mask for the endless daylight in Alaska.

On the opposite side are two rectangular pockets seemingly meant for a phone and a battery charging pack. These pockets, however, have no closure system. My phone and battery pack always fell out despite how many times I tried to keep them secure. Unfortunately, I found these two pockets essentially useless.

Down near the waist, there are two stretch mesh pockets designed for larger items, fitting a 1L Nalgene bottle or a large 16-ounce isobutane fuel canister perfectly. I found these pockets super useful, and they kept these larger items warm and prevented them from rolling around into uncomfortable places.


After spending over 35 nights in the Marmot Col -20-Degree this spring, my favorite characteristic was simply how comfortable it was. The inner lining of the bag is a bit thicker and softer than materials found on ultralight sleeping bags. It was much nicer against the skin than similar bags. No more sticky, oily-feeling fabric against the skin leading to an uncomfortable night’s sleep.

If the dimensions of this sleeping bag don’t give you an idea of its size, just know that this bag is spacious! I’m 6’0” and 150 pounds, and the size Regular felt like living in a small hotel.

At 83 inches long, there was ample room in the footbox to store items I wanted to sleep with, such as extra layers, fuel canisters, warm bottles of water, or battery charging packs. A couple of nights before early alpine starts, I slept comfortably with both of my size 43 SCARPA Phantom 6000 double boots in the footbox.

The ample chest width of the bag meant that I could layer up easily inside the bag if needed, even with a large summit parka. The sleeping bag was so spacious that I felt it was sometimes too roomy for my thin frame.

My solution was to layer one of my jackets on top of me to take up some of the interior volume. And I still had tons of room to roll and rotate throughout the night. For larger-framed folks, just know there was no shortage of interior space!


Marmot Col -20 Sleeping Bag stuffed in bag on snow
Stuffed (without compression bag) size of the Marmot Col -20-Degree; (photo/Christian Black)

The downside of the necessary loft and generous interior space was packability, as can be seen in the image above (Nalgene 1L bottle for scale). Similar to other expedition-appropriate bags, cramming the Marmot Col -20-Degree into a pack could be challenging.

The included stuff sack doesn’t have compression straps, which would shrink the monster bag to a more manageable size. But Marmot provides a compression sack with current models (ours was a pre-production sample).


As far as warmth goes, the lower temperature limit of the bag at -20 degrees Fahrenheit seemed about right. Multiple nights in the -15-degree F range had me slightly chilly, but that was sleeping only in thermals. At 14,000- and 17,000-foot camps on Denali, I slept in a light synthetic layer such as a Patagonia Nano-Air Hoody to add warmth.

But this was likely necessary because the bag is very spacious, and I have a small upper frame. I imagine a body type that fills out the bag better would have better warmth.

Marmot Col -20-Degree Sleeping Bag: Conclusions

Col -20 partially open showing lower pockets
The lower pockets were ideal for water bottles and fuel canisters; (photo/Christian Black)

After over a month of sleeping in the Marmot Col -20-Degree bag (MSRP $829) on both the Tokisitna Glacier and throughout a climb of Denali’s West Buttress, my general impression of the bag was very good. I loved how comfortable against the skin and plush it always felt, helping me achieve a great night’s sleep.

The zipper and pockets were all generally high-quality and useful, aside from my gripes about the exterior vent zippers and the phone pocket.

The spacious interior was extremely useful for sleeping with anything I needed to keep warm.

Even though the Col is not the lightest bag in its category, I thought it was a perfect choice for expedition-style climbs where it will likely be carried in a sled 90% of the time. The challenging packability and volume would be less noticeable.

Check Price at Marmot

The Best Backpacking Sleeping Bags of 2023

A sleeping bag is one of your most important pieces of camping gear. We've found the best backpacking sleeping bags for every use and budget. Read more…

Subscribe Now

Sign up to receive GearJunkie content direct to your inbox.

Subscribe Now

Sign up to receive GearJunkie content direct to your inbox.