Kelty Cosmic Ultra 0

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Overall

#134 in

Outdoor Sleeping Bags

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Sentiment score60% positive
3
1
1
Last updated: May 9, 2026

Reddit Reviews

Reddit Iconflobbley
about 2 months ago

Some tent options https://www.kaviso.com/collections/tents-shelters/products/sierra-designs-full-moon-2p-3p-tent https://www.campsaver.com/kelty-late-start-2p-tent.html https://www.naturehike.com/products/mongar-2-person-ultralight-backpacking-tent Sleeping bag: You're not going to find a sleeping bag that keeps you warm at 20°, packs up to a reasonable size, and costs less than $75. Your best bet is to hope for a deal on marketplace or get a down camp blanket and use it with your current sleeping bag. Sleeping pad: https://www.backcountry.com/therm-a-rest-prolite-plus-sleeping-pad-womens https://www.als.com/sea-to-summit-camp-self-inflating-sleeping-pad-10350624/p https://www.walmart.com/ip/Featherstone-El-Cordion-Insulated-Closed-Cell-Foam-Sleeping-Pad-for-Camping/167563817

about 2 months ago

Do you actually need a bag that keeps you warm at 20F or are you just looking for a 20F bag? for context most bags are named for their limit rating, where you'll start to feel pretty cold. So for example a Kelty Cosmic Down 20F will keep you warm down to about 32F, that temperature is the comfort rating. The reason I ask is that bags really start to ramp up in price when the comfort ratings get below 32F. 20F limit rating bags (bags that will keep you warm to 32F) are common, 5-10F limit rating bags (what you'd need to be warm at 20F) are not as common

about 2 months ago

No problem at all. My personal favorite cold weather sleeping bag is the Sierra Designs Mobile Mummy 15, which I've used into the low 20s but I don't think they sell it anymore. You could go two ways with it, you could get one bag that would keep you warm by itself down to 20F, or you could get a sleeping bag and a camp blanket. The sleeping bag would keep you warm down to freezing, then when you add the blanket on top it would give you another 5-10 degrees of warmth. That would also add more flexibility for temp ranges. If you want to go the first route this is the best bang for buck I could find, the upsides are that it's down which means it will pack much smaller than any comparable synthetic insulated bag and is lighter than a 2-bag system. the downsides are that it will probably be too hot for warmer weather camping and since it doesn't have a hood you'll have to wear something on your head to keep it warm at night: https://www.kaviso.com/collections/sleeping-bags/products/kelty-supernova-0-degree-sleeping-bag?variant=45681345462500 If you want to go the second route here are the good bang for buck sleeping bags I found: https://www.rei.com/product/C00655/mountain-hardwear-lamina-eco-af-15f-9c-sleeping-bag https://www.rei.com/product/250709/marmot-sawtooth-sleeping-bag-mens https://www.pariaoutdoorproducts.com/collections/affordable-backpacking-gear-sleeping-bags-pads/products/thermodown-15-backpacking-sleeping-bag?variant=11778285191 The first is synthetic, the second two are down. If you get one of those add a cheap camping blanket from Amazon. Here are some examples, the first one I have and was pleasantly surprised by the quality, the second one I know nothing about but I like the foot drawcord, and the third is one I've heard someone else say they like: https://a.co/d/0bSS6yGR https://a.co/d/0bxxSp2f https://a.co/d/01kbAOW2 It goes without saying that you should do your own research into any of these bags before pulling the trigger, I've only done a cursory review of each.

about 2 months ago

I just stumbled on this bag while looking at something unrelated, I have the 20F version of this bag and find it to be quite comfortable for me personally. This one comes to ~$172 after applying the coupon. https://www.campsaver.com/kelty-cosmic-ultra-0-sleeping-bag.html

Reddit Iconkaz1030
7 months ago

The typical weather in coastal PNW this time of year is lows in the mid 40s and I used to bring a Sierra Designs 20F synthetic bag, but with humidity at 90% and Pacific winds, it isn't comfortable. A fleece liner and extra blankets didn't make a difference so I now just bring a Kelty Cosmic 0 degree down bag.

Reddit Iconratcnc
6 months ago

A Kelty Cosmic 0° is around $200. It’s the often mentioned low cost down bag. It will cut your weight in half.

Reddit Iconjorwyn
7 months ago

My Kelty 0F that's not a mummy bag because I find those very annoying.

Reddit Iconolerndurt
6 months ago

I have a Kelly 0F bag, 15F or so was still very cold and I had to stay bundled the whole time. 3 season North Face tent.

Reddit IconHelpful_Affect_7958
7 months ago

My Kelty 0 bag, so I can wear shorts and t shirt and still be comfortable

Reddit IconVote_Knope_2020
11 months ago

I have the single version of this and also love it. Super versatile temp-wise.

Reddit Iconelevatedtoast
9 months ago

Also have this Kelty bag and was pleased with its performance this spring. I do have the eco version of it as it was at sierra for a solid deal. With temps down in the low 40’s upper 30’s, I was warm with layers on.

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