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Marmot Aspen 40 Ultralight

rated 4.0 of 5 stars

The Aspen 40 Ultralight has been discontinued. If you're looking for something new, check out the best warm weather down sleeping bags for 2024.

photo: Marmot Aspen 40 Ultralight warm weather down sleeping bag

A lightweight, 1.5 pound, 600 down fill summer sleeping bag. This line of Marmot sleeping bags was made exclusively for Dick's sporting goods; the current Marmot Aspen bag sold at Dick's has synthetic insulation. The closest match to this bag today is a Marmot Always Summer. If you can find one, it's a great choice for summer backpacking and cycling.


  • Very lightweight
  • No feathers have come out, with heavy use, since 2009
  • Full hood


  • A true 40 degree bag — don't push the rating
  • Developed cold spots — use a liner or wear a base layer if this bothers you
  • Zipper tends to snag on the way up

I walked into Dick's Sporting Goods one day in 2009 and ended up with a few things not on my list, this Marmot Aspen 40 degree ultralight bag being one of them.  I've put this bag through a lot since then, including several multi-day hiking and biking trips, and I haven't regretted my investment.  That being said, there are a few things that bug me, including a zipper that tends to snag on the way up (but not down — go figure), and sewn through construction that gives me a cold spot in my hip area.  This is why it only gets 4 stars.

Dick's has still has a line of Marmot Aspen bags made exclusively for it by Marmot, but the current Aspen ultralight has synthetic insulation. So I'll be comparing it to the closest current version I can find and actually play with, the Marmot Always Summer 40 degree bag.


The bag's shell seems to be made of tricot nylon, and I can't see through it so it's a bit thicker than some newer ultralight bags. No feathers have come through the lining, so I've either been lucky, or it's just good material.  The bag is filled with 9 oz of 600 fill down. It has a draft tube and a full hood unlike some other summer bags.  I like a hood as it keeps whatever I'm using as a pillow in place.  The bag has two hanging loops in the boxed foot area.  There is a drawcord and zipper cover at the top along with a small zippered pocket.  No issues with seams.



In comparison, the Marmot Always Summer has 9.8 oz of 650 fill down, with a slightly stretchy nylon shell, and a different baffling system that may reduce the cold spots I feel in mine. The bag isn't mine, so I can't sleep in it, but the Always Summer does seem like an improvement for a bit more weight.



My bag weighs 1.5 lbs with the supplied Marmot XXS stuff sack. The stuff sack isn't waterproof, and the bag can be compressed a bit smaller than what the including stuff sack can do, but doing so makes the bag a hard little rock.  I can fit it, a Big Agnes air pad, and a Big Agnes SL1 in the bottom compartment of my backpack. A cotton storage sack was also included.  My bag is about 70" long and 28" at the widest point.  For me, 5'10" 180lbs, the bag is a comfortable size.  I don't like bags that hug you too close.

In comparison, the Marmot Always Summer is built a bit different and seems to be a bit smaller inside to me.



The bag is rated to 40 degrees. I've used this bag in temperatures as cold as 30 degrees on top of a Big Agnes insulated air pad and got cold even with a base layer. I'm a cold sleeper, so this was expected, but 30 degree temps on that outing were not.  So I've learned to use this bag only in the summer, and it's great for that.


A great Marmot bag that's fit for its intended purpose; a lightweight summer bag.  It is a no-frills bag and is almost like a stripped-down Marmot Always Summer. Even though it's a Dick's exclusive bag, it's still a Marmot, and the Marmot warranty is the same as any other bag - I just haven't had to use it.  It makes me willing to try other Marmot-branded gear at Dick's and other sporting good stores, the corners may have been cut a little to reduce the cost, but the quality holds.

Source: bought it new
Price Paid: $90

Needed to cut down on weight for summer backpacking and this was the answer. Very light, packs down to the size of a grapefruit, and really does the job.


  • Packs incredibly small
  • Very light
  • Lots of foot room


  • Probably not the best wet weather choice
  • 2-way zipper sticks

I realize that this was a Dick's Sport exclusive, but it still has the Marmot name and built in quality. The stitching is excellent and keeps the down in place. I'm 5'11" and 200 pounds. The bag has plenty of room in the hips and shoulders and a squarer foot box than my 3-season bag. I like to toss and turn, so this was perfect. 

The exterior is a polymide and the interior lining is nylon. The fill is 80% down and 20% feathers. Rated at 40 degrees it kept me warm in the Colorado mountains in August, which is all I wanted. 

A 3/4 2-way zipper makes getting in and out easy, although my lower zipper pull does stick a lot. There isn't a whole lot of insulation in this bag, so I would avoid getting it wet. 

I pack it into a Marmot XXS stuff sack. It is as small as a grapefruit and less than 2 pounds. Always store it hanging and the loft puffs up very quickly

Source: received it as a personal gift

The bag is rated at 40 degrees, works pretty good to that temp. It's very lightweight at 1.5 lbs. It's a good summer bag!


  • Lightweight
  • Comfortable


  • The foot box could be a bit bigger
  • It's a very tight fitting bag.

I bought this bag last summer and used it in warmer nights than its specified 40 degree temp, so used it as a quilt just laid over me at night. It's very lightweight at 1 1/2 lbs and stuffs into a compression stuff sack. It's filled with Polarguard and compresses very well to the size of a soccer ball, so takes up very little room in my backpack or bike panniers.

It's a very tight fitting bag and the foot box could be a bit larger, especially for someone like me with big feet (13's)

At temps below 40 I use sweatpants and a sweater to keep me warmer.

I bought it at Goodwill for $5, but I think it retails for about $95?

Source: bought it used
Price Paid: Used/like new $5

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