This Sleeping Bag Liner Is Perfect for Fall and Winter Camping, and It's 20% Off Right Now

An extra layer when you need it most

Photo: REI

The Cocoon Silk Mummy Liner is designed to boost your sleeping bag’s temperature rating by up to 8.4 degrees Fahrenheit. This makes a 0-degree bag warm enough for winter camping in many mountainous locations and makes a 30-degree bag suitable for nights like the one described above. No matter how durable or reinforced your tent is, it’s the temperature in your sleeping bag that really matters.

The liner weighs just 4.7 ounces and stuffs into a 3-inch by 6-inch sack. As such, it takes up next to no room in your backpack, and what I’ve started doing is keeping it inside my sleeping bag. That way, I always have the liner with me if I need it. At 95 inches long by 35 inches wide, it’s both tall and wide enough for just about anyone. I’m 5’7” and enjoy the lack of crowding when using the liner. In fact, on more than one occasion I’ve forgotten that it’s even there, and have exited and rolled up my sleeping bag with the liner still inside.

Another plus of the Cocoon Silk Mummy Liner is its durability. No matter your outdoor pursuits of choice, it’s there for you. The liner is great for canoe and raft trips when sleeping waterside makes for cooler nights. For overnight backpacking trips, it gives you the versatility to choose a wider range of campsites even if some are more exposed.

How the Cocoon Silk Mummy Liner performs in snowy conditions during winter camping

The first time I ever used my Cocoon Silk Mummy Liner was on an overnight splitboarding expedition in the Colorado backcountry in early March. We camped at 10,000 feet. It had just snowed unexpectedly, and as such, forecasts called for temperatures close to 0 degrees overnight. As I said goodnight to my fellow campers around the fire, I mentally prepared myself for a long night with frequent wakeups due to cold temperatures.

I slept in normal pajamas — including long cotton pants and a long-sleeve shirt — in a mummy sleeping bag rated to 15 degrees. Using the liner kept me much warmer throughout the night than I’d expected. The first time I awoke and checked the time on my phone, I was in disbelief — it was nearly 7:00 AM. I’d slept through the night without any of the hiccups I’d envisioned, and was warm enough that I easily found the motivation to get up and melt snow for coffee, to boot.

Cocoon Silk Mummy Liner: Decision-making factors on whether to buy

Photo: REI

In addition to its durability while camping and backpacking, the liner has a major perk for travelers. It’s ideal for when you’re staying in hostels or less-than-clean hotel rooms and want an extra layer of protection from the sheets. In warm climates, you can even use the liner in place of a comforter or linen, as its thin silk lining is enough to keep you warm and provide that familiar feeling of being tucked into bed, without getting too toasty.

Sleeping out under the stars is the best way to make use of the Cocoon Silk Mummy Liner during warm summer nights. I learned this on a clear July evening and can confirm that opening your eyes to the Milky Way is much more inspiring a view than the inside of a dark tent.

Downsides to the Cocoon Silk Mummy Liner

The one complaint I have about the Cocoon Silk Mummy Liner is that I’ve found it easiest to get myself into the liner first, and then into the sleeping bag after, which can be tricky in a tight tent. It’s never been impossible to do, and indeed this is more a personal gripe than a functional issue. What I now do on multi-night camping trips is leave the liner inside the bag from start to finish.

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