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Call it a 3.5-season.

There really isn't any such thing as a year-round sleeping bag. It would either be too cold in the winter or too hot in the summer. The Kelty Cosmic 0-Degree Down Sleeping Bag is about as close as you can come to year-round comfort. The 0-degreee rating means this bag will keep you comfortable from early spring to late fall without getting super hot in the middle of summer. The down fill also means that the Cosmic is lightweight and extremely packable.

  • 0-degreee rating for comfortable camping all year except for the middle of winter
  • Down fill is ultralight and ultra-packable
  • Mummy shape for efficient insulation and minimal pack size
  • Soft, durable 50D polyester taffeta shell and liner fabric
  • Insulated hood baffle for head-to-toe warmth
  • 3/4-length zipper for reduced weight
  • Two-way locking zipper won't open in your sleep
  • Zipper draft tube seals out drafts
  • Anti-snag zipper design for no more stuck zippers
  • Differential cut and slant baffle construction eliminates cold spots
  • Ground-level seams help prevent heat from escaping
  • Sleeping pad and security loops keep everything in place
  • Internal liner loops keep your liner from wandering
  • Fatman and ribbon drawcords are easy to find and grab in the dark
  • Stuff sack included

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Kelty Cosmic 0/EN 4 Sleeping Bag: 0 Degree Down

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Here's what others have to say...

5 5

Good Value

  • Familiarity: I've used it several times

I purchased this bag after my other bag sustained a zipper malfunction. I had never purchased a down bag and was looking for one rated for zero degree weather. My first night on the trail with this bag was on a 9-degree night in January. The bag performed very well. I noticed another review saying that it did not come with a stuff sack but it is supposed to. I did get a stuff sack with my purchase from BackCountry. My only complaint with this bag is that for me it is a little too narrow across the shoulders. I have an athletic build and would have loved for this to be just a little wider. My group and I are pretty much cold weather hikers & campers. We hike in fall, winter and early spring and then we shut it down. We had a very cold winter this year and I spent 7 nights with this bag in single digit temps and it was nice & toasty. As far as 0-degree bags go I would recommend this one. Wait for it to go on sale and jump on it. You won't be disappointed.

5 5

Works great...

  • Gender: Male
  • Familiarity: I've used it several times

Bought this bag a few weeks back in anticipation for a very early Spring backpack jaunt into one of the coldest basins in Colorado @ 12,000' to climb and tent camp on a few feet of snow. Bag was ideal for the dollars spent. Temps were in the single digits both nights and I was toasty with just one layer on and never fully tightened the top. I do sleep on a Big Agnes SL which probably made a big difference as the person next to me was on a standard Thermarest with a different brand 0 degree down bag and said she slept cold. Packed great and the cheap price was not too compromised with extra weight to carry. I carried my MH Bivy bag "just in case" I needed a few extra degrees, but it was never needed. I am 5'8" and the regular had plenty of space for the flip-flopping I usually do. I am very happy and impressed with this bag, delightfully surprised is more like it. Never thought I'd be a Kelty guy, but my opinion has been changed. Best part is I have a few extra dollars in my pocket to buy more gear.

5 5

Great 0 degree Backpacking Bag!

My Wife & I picked this bag out for her backpacking sleeping bag & we are so happy with our decision! It is really compressible & fairly lightweight. Looks great & is VERY affordable also! So far not one complaint. It would be nice if the bag did come with a compression sack but for the price whatever!

How bulky is it? Is it a good backpacking...

How bulky is it? Is it a good backpacking sleeping bag? I mean for the price

Best Answer Responded on

The Kelty Cosmic 0/EN 4 Sleeping Bag employs 550 fill down which generally is going to be more compressible and warmer than synthetic insulating alternatives. According to the specs on this bag it should compress to 9"x17" (regular) which is fairly good for a 0 degree bag. It also has a weight of 3lbs 12 oz. (regular), which means it is fairly light and would make a good backpacking bag.

There are more compressible bags out there and lighter ones too, but for the price the Kelty Cosmic is hard to beat. As an alternative I would look at the Marmot Sawtooth bag. It is 15 degrees instead of 0, but it is light and slightly more packable at about the same price.

4 5

Good value

  • Familiarity: I've put it through the wringer

I've had this sleeping bag for 4 seasons now and I can agree that it's super versatile as far as when you can use it, comfortable, durable, packable, etc FOR THE PRICE. It's definitely not as light as some of the other 0 degree down sleeping bags out there, but for the price it will definitely keep you warm in somewhat cold weather and be light enough to take with you on backpacking trips.

One thing I've noticed since I've had this bag is it doesn't keep me super warm... could be because the down fill is lower than some (only 550 fill), but it makes it good for spring, summer, fall, and milder winter camping.

Overall I would recommend this product if you don't want to drop the money for a more expensive, higher fill, lighter weight bag. It's a good value and has treated me well.