How to Choose Sleeping Bags for Backpacking
NEMO Sonic Sleeping Bag
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An ingenious 850-fill-power cold-weather down backpacking bag, the NEMO Sonic 0 has gills that allow you to regulate the internal temperature by as much as 20°F without letting cold drafts inside.
Shop newer versionKey Details
Fill
850-fill-power down
Temperature Rating (F)
0 degrees (F)
- Premium 850-fill-power duck down offers maximum loft and warmth at minimal weight, yet compresses down small
- Stretch construction at the knees helps maintain bag shape, thermal efficiency, and loft, while offering enhanced volume so you can sleep on your side or with your knees bent
- Adjustable Thermo Gills allow regulation of the internal temperature
- Nylon shell has a light waterproof breathable coating on the backside of the fabric and a durable water repellent on the exterior to protect against moisture and condensation
- Waterproof breathable footbox protects down from tent wall condensation and enhances comfort
- Internal draft collar seals in heat and blocks out cold
- Drawstring stuff sack and a cotton storage bag included
- Winner of Backpacker magazine's 2015 Editors' Choice Award
Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Backpacking bags are typically rated for temperature according to an independent testing protocol—currently International Organization for Standardization (ISO) 23537, though some older items followed European Norm (EN) 13537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.
Each bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
View all NEMO Backpacking Sleeping BagsEach bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
| Best Use | Backpacking |
|---|---|
| Tested Lower Limit | 0.2 degrees (F) - EN |
| Tested Comfort | 13.8 degrees (F) - EN |
| Temperature Rating (F) | 0 degrees (F) |
| Temperature Rating (C) | -18 degrees (C) |
| Shell | 20-denier ripstop nylon |
| Zipper Location | Left |
| Insulation Type | Down |
| Fill | 850-fill-power down |
| Lining | 20-denier ripstop nylon |
| Sleeping Bag Shape | Mummy |
| Compressed Volume | Unavailable |
| Gender | Unisex |
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vws44
Wyoming
Comes as Billed
8 years ago
I have used this bag primarily in the Bighorn Mountains of Wyoming. After a couple of winter ascents of Cloud Peak and Blacktooth, I couldn't recommend this bag highly enough. The stretch in the knees makes a great difference and the draft collar is incredible. I have taken this bag into the single digits and been toasty. I think the gills make a noticeable difference, but I think that 20 degrees might be a stretch. Also, while the pockets around the neck are nice, the zippers and materials are prone to snagging. However, for the price, this bag is a steal. The stuff sack is a joke, but I have yet to find a provided stuff sack that I'd actually use.
Keith and Kiva
Mount Laurel, NJ
Great Warm Bag
9 years ago
Spent the past two weeks on the AT in NY and New England with my dog. The first week, the weather was absolutely miserable - cold (teens and low 20's at night), high winds (20-40 mph), rain, snow and sleet. This bag kept me very, very warm at night without any issues whatsoever. Needed to "learn" the pull string system for the collar and the upper baffle, since with these loose, you lose the heat from the bag and you tend to get slightly chilly. Once I figured this out, no issues whatsoever. No cold spots. The footbox is warm and plenty big enough (and also waterproof). I have the "long"model - I'm 6' and 195 lbs - and it was perfect. I'm also a side sleeper and this bag is exceptional for that. A very lightweight, very warm, high-quality sleeping bag.
HaroldMith
Home grown, internationally known
Toasty and Roomy
9 years ago
Being a cold sleeper I wanted a low rating bag that would work ideally in the 20-40 degrees range with the ability to go lower if needed. My experience with other bags is the stated temp rating is a bit of a stretch and I'm cold when approaching that stated degree. With the Sonic the bag is a 0 degree with a 13 degree temp rating. Ive used several times with temps being at 30 and Im toasty warm. My favorite thing is the roomyness in the bag. I was first drawn to Nemo spoon shaped bags but quickly realized the Nocturne temps wouldn't do it for me. This is the big shoulder and hip circumference bag I found on the market. The other thing is I want my down to be puffy and comfy not thin. This is 850 fill about the best you can get. I absolutely love this bag is lightweight so can travel great and would recommend to all. Im 6'1 220 and got the long.
Hike8891
03251
Winter NH - Whites
10 years ago
Awesome bag. Mainly used in the NH-Whites this past winter. Every time I woke up in the AM it was well below zero outside and I was plenty warm all night. No issues with zipper and the bag still looks in great shape after a year of use.
Fgray4
Denver, CO, United States
Rocked the Kilimanjaro Trek
9 years ago
I begged, borrowed and was willing steal to get this bag before my trip to Kilimanjaro and it was worth it. I am 6ft tall and I highly recommend the Sonic long bag. This bag was incredible every step of the way up Kilimanjaro all the way up to base camp 16,000ft with temps from 15 to minus 8-10 degrees. I tend to run a bit warm in general, slept in my boxers and t-shirt for the entire trip with the vents open. Amazing bag, worth every penny. Roomy and easy to stretch out into several sleeping positions. I have had Camp 7 and Monte Bell bags before and this one smokes them all for comfort and warmth. Very lightweight. Stuff bag it comes with is could but it could even pack down smaller if needed. SOLID GEAR!
Yes , I recommend this product
Originally posted on nemoequipment.com
Rocky road
Seattle, WA, United States
Extremely light and roomy for us side sleepers.
8 years ago
Im 6ft 260lbs I purchased the long bag during the summer and I finally got to use it. Traveled up to Mt. Rainer two weekends ago where the temperature got down to around 25 degrees during the night with between 30 and 40mph winds. I think it held up pretty well with just the underarmour cold gear base layer and Exped downmat sleeping pad. But I'm kinda curious if it's worthy of extreme temperatures like zero or even hitting negative Temps. I guess with the right layers anything is possible. I'm bound to find out after the New Year.
Yes , I recommend this product
NotB
California
Roomy, Light, and WARM
8 years ago
I have used this bag down to 15 degrees just in my boxers and been cozy. I am 6'4, 205 so room was a big deal for me. The room I had in this bag compared to the weight of the bag is amazing. Finally,the draft zips have helped keep me comfortable with the bag zipped in temps up to the mid 30's. Pricey but totally worth it.
Yes , I recommend this product
Sandra G
Philadelphia, PA, United States
Warm and cozy
8 years ago
I've used this bag on nights down to 25 degrees with fierce winds. This bag kept me warm with only base layers on. The regular size is 6 feet, so I had to stuff my down jacket into the footbox and there is enough room to rotate onto my side.
Yes , I recommend this product
Travelalot1
Parker, co
Got down to 10 degrees
9 years ago
I gave this a test in the yard in a bivy in the snow. I thought it was pretty warm and could maybe even toasty with the right layers. I did get a little cold toward around the 3 am mark and went inside. I later realized that I was shipped a long bag which I don't need so I think I just had too much space which got cold. I also only wore a mid weight base layer. I will test again with another layer and feel confident I could go colder and all night.
ARV
Denver, Co
warm and light weigh
9 years ago
This sleeping bag was used on a trip to Alaska in Sept 2015. My camp was above timberline. this bag is extremely light weight and was very warm.
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