NEMO

Sonic -20 Sleeping Bag

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Overall

#219 in

Outdoor Sleeping Bags

according to Reddit Icon Reddit

Sentiment score50% positive
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1
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Last updated: Apr 19, 2026

Reddit Reviews

Reddit IconKcamyo
5 months ago

You got me thinking. I might be safer to just get the Nemo then. Realistically, I doubt I will be outdoors below -20C. At least with the Nemo, it’s pretty versatile

5 months ago

Thanks for the feedback. I’m leaning toward the NEMO -20°F now. A few people told me to go with a -40°F to be safe, but I’d like a bag I can actually use across different conditions. I just don’t want to make the mistake of choosing the wrong one, since this is basically a lifetime purchase, at least I hope. I’m using the Tensor All-Season pad, which I believe is around an R-value of 5.5. Definitely could go higher

5 months ago

I got the Nemo -20!! Went on sale so I had to grab. thank you for everyones help

3 months ago

correct, Nemo Sonic -20F

3 months ago

It’s been great so far. I don’t have other winter bags to compare it to at the moment, but it packs down surprisingly small and is fairly lightweight for a true winter bag. The hooded head design does a really good job of sealing in warmth, especially in colder temps, though I can see how it might not be for everyone, if you don’t like a more enclosed feel around your head, it could take some getting used to. Nemo’s warranty and customer support have also been solid. It took me a while to decide, but it ultimately came down to value, I found this on sale for about $300 less, which made the decision easy.

Reddit IconSuitable_Sentence_46
6 months ago

I like the Nemo sleeping bags that have the gills. You can open them when it's warmer and zip them up as the temperature drops. Works much better for me than just opening the side zipper, which I find let's too much heat out.

Reddit IconAlfnadoawaywoah
8 months ago

This. I hate mummy bags. I move too much in my sleep. My Nemo takes up a bit more space in my pack but it is so comfortable and a good night’s sleep, where I can fully roll around in my bag, is worth it. I will never go back to a mummy bag.

Reddit IconBiggyBiggs
about 2 months ago

It might depend on how you're built, but I can get my leg up like that inside my Nemo bag. I have short legs, though.

Reddit IconCrazylady5665
5 months ago

I really wanted to love the Nemo, but if OP is a smaller person, Id warn they have too much dead space.

Reddit IconDinoAndFriends
about 2 months ago

I'm a side/stomach sleeper and love my Nemo sleeping bag. I have a synthetic one and it's quite bulky, but the down ones would compress better.

Reddit IconEducatorOk9409
about 2 months ago

This! I love the little zippers on top to help with warmer nights. A knee is always moving up or down and I have just enough room for that at 5'10.

Reddit IconFL00D_Z0N3
4 months ago

If your biggest concern about a sleeping bag is room for your legs to move without feeling constricted, I would try out Nemo or Big Agnes sleeping bags. Both tend to have wider profiles. Definitely go for a bag that is rated at least 10 degrees lower - preferably lower - than the temps you expect to sleep in. Theres multiple problems with layering with clothing like this, one of which is not the warmth specific factor but the breathability. One or two layers is one thing, but with all the listed clothing and then something like the picture on top, you’re going to build up humidity near your body you can’t get rid of, and you’ll become even colder. Next, a sleeping bag basically creates a warm pocket of air around you. The insulation in the bag helps create and maintain this pocket. The more compressed this insulation, the worse it performs. With layering clothing, you compress the insulation, making it less effective. On top of that, insulation is minimal if not nonexistent at the seams. Some puffy jackets and “extreme temp” clothing gets around this by minimizing seams but there’s almost always a few somewhere, which means no air pockets and no warmth. If I could recommend the best case scenario for you, it would be this: find a sleeping bag you can tolerate rated to a temp appropriate for your conditions, 15F at a minimum, best scenario a 0F. Dress in only your smartwool layers, and make sure you have a good pad/sleep set up underneath you. Sources: avid outdoorsmen, backpacker in sub 20 degree temps, and former REI employee who specialized in camping gear.

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