Gear Review: REI Magma 30 Sleeping Bag

I’d been in the market for a new sleeping bag for a while. My 55-degree bag was light, but only useful for summer trips at lower elevations. My older 20-degree bag kept me comfortable at temperatures below freezing, but was stifling in warmer weather, and was too heavy. I was looking for that “Goldilocks” bag that could handle shoulder-season trips without a huge price to pay in weight, cost, or warm-weather comfort. I jumped at the chance to test the REI Magma 30.

REI Magma 30 At-a-Glance

Weight: Regular is 1 pound, 4 ounces; Long is 1 pound, 6 ounces
Fill: Water Resistant 850 “Power” Goose Down
Temperature Rating: Lower limit 30 degrees; Comfort limit 39 degrees
MSRP: $319 Regular; $339 Long

REI Magma 30 Overview

Note insulated yoke

As I’m 6’ 3”, I opted for the long version. Those six feet or under would be fine with the regular. The bag comes with a large mesh storage bag and an incredibly small stuff sack. The outer shell is water resistant Pertex 15-denier ripstop nylon and the inner lining is a comfortable 15-denier ripstop nylon. (Both the inner and outer linings are Bluesign approved) In between is 850 fill, water resistant goose down certified to the Responsible Down Standard. The advertised weight is 1 pound, 6 ounces for the long (which matches my scale) and 1 pound, 4 ounces for the regular. REI claims the Magma has the best warmth-to-weight ratio of their lineup.

The zipper is large, runs smoothly and is backed with a draft tube to help seal in warmth. While not full length, the zipper is longer than ¾ zipper models I’ve owned. The hood is adjustable from inside the bag and holds a small inflatable pillow very well. The bag also has an insulated yoke. The purpose is to fill the space around the neck and shoulders preventing heat loss. My initial impression of the bag was very good. Manufacturing quality was high,


Plenty of room for me, my size 13 feet and a pillow. Insulated yoke is out of the way for warmer weather.

As mentioned before, I tested the long version. At 6′ 3″ I’m right in the middle of the 72-78″ height that the Long targets. The bag is cut in the “mummy” shape which results in a shoulder girth of 63” and hip girth of 57″. In addition, the foot box handled my size 13 feet without issue. Overall sizing was generous for such a lightweight bag and roomy enough to allow me to do my typical “flopping around” without getting bound up. On the other hand, the bag was not so large that it became difficult the heat any superfluous space.

Other mummy bags that I looked at were either heavier (Nemo Riff 30) or sized for a tighter fit (Big Agnes Flume UL 30, Therm-a-Rest Hyperion 32). All three were more expensive. The Magma hit the sweet spot for sizing.


Pillow tucked securely in the hood, Easy to grab zipper grabs are both inside and out.

The Magma uses 850 fill down to provide excellent warmth and compressibility for its weight. (900 fill is the best commercially available down.) The down is also treated for water repellency, so the bag is designed to continue to retain its insulating properties when damp.

In the product description, REI states: “Variable baffle spacing locates and stabilizes the down fill, delivering high thermal efficiency and reducing weight.” What that meant in real world testing was no cold spots when the temperature dropped, a real plus.

Also helping during the coldest use is the insulated yoke. It sits in the shoulder/neck area and seals off the cold draft that can be let in when moving around.

If you like using a small pillow, the hood works very well to hold it in place. No pillow or very cold, the hood adjusts to seal your head and even much of your face from the elements.

The zipper is a long 3/4 length and can be opened at the bottom if your feet get too warm. The pull is easy to grab and an internal antisnag strip mean it zips smoothly. The zipper’s path veers off the side for easy access along the shoulders and upper torso. The length of the zipper is backed with a draft tube for maximum warmth when closed up tight.

Temperature Rating Accuracy

Settled in for coldest conditions. Note how the zipper curves to be easily reached.

The Magma 30 has a “comfort” rating of 39 degrees Fahrenheit and a “lower limit” rating of 30. Per the REI website: The Comfort/T-Comfort rating is the lowest temperature at which the bag will keep the average “cold sleeper” comfortable, and the Lower Limit/T-Limit rating is the lowest temperature at which the bag will keep the average “warm sleeper” comfortable. Ratings are based on a person wearing one long underwear layer and a hat, sleeping on a single 1 in. thick insulating pad.

During my testing, I spent nights in the bag when the temperature was both in the lower 40s and the lower 30s. Unlike other bags I’ve tried, the Magma seemed to be spot on with its temperature rating. In the low 40s I was plenty warm in just underwear and a t-shirt. In the low 30s I was comfortable while dressed just as the website described, in one long underwear layer and a hat.


Soon after receiving the bag in early May, I planned a couple short trips to Zaleski State Forest in Ohio. The second thing I noticed about the bag was how small it packed down when using the included stuff sack. The first thing I noticed was how hard and time consuming it was to get the Magma into that sack.

Assuming a regular-size bag gets the same stuff sack, it would be a bit easier, but still a battle. As I’d rather spend my mornings hiking instead of fighting my sleeping bag, I used a larger stuff sack for the trips.

The weather was warm camping in Ohio. The bag performed well and the zipper never snagged as I treated it more like an open quilt due to the heat. A better test was conducted in northern Michigan while hiking the Lakeshore Trail, the 42+ mile portion of the North Country Trail that runs the length of Pictured Rocks National Lakeshore.

It had been a cold, snowy winter in northern Michigan and snow and ice still lingered in spots during my trip. The weather forecast promised variable conditions including wet and cold near the limit of the bag. In addition to the Magma 30, I was using an ExPed SynMat HL pad which contains insulation with an R-value of 3.3. My tent was a Gossamer Gear The One, single-wall tent.

After a pleasant 12-mile day my first camp was behind some dunes, about 100 feet from Lake Superior. The bag remained comfortable as the temperature dropped through the night and rain showers rolled through. In the morning it was cloudy, windy and around 40 degrees. The tent was rain covered on the outside and condensation covered on the inside, but the bag remained warm. My pillow stayed in the hood. The bag was not restrictive and the neck yoke did a surprisingly good job of stopping drafts as I switched positions through the night.

In the morning I wiped away as much moisture as possible from the tent, but it was still packed out wet. The Magma was damp to the touch and packed up in that condition. The temperature remained in the low 40’s throughout the day and there were periods of showers to go with a cold wind off the lake. Thankfully, the scenery was spectacular, taking my mind off the unpleasant conditions.

After a 15-mile day I set up camp near one of the visual highlights of the trip, Chapel Rock. The tent was pitched next to Chapel Creek approximately 200 feet from Lake Superior. The bag was going to get the full test when it came to handling moisture; short of me drenching it in the lake.

Single wall tent, next to a stream, near Lake Superior, in rainy, cold weather. Doing everything I could to test the Magma’s ability to keep me warm.

The clouds broke up a bit and the ongoing wind did allow the tent to dry off before I turned in for the night. The bag, as expected, was a bit clammy when I fluffed it out in the tent. I still warmed up quickly once inside it.

The temperature dropped through the night and I awoke in the morning to a light sleet hitting the tent. It was approximately 32-34 degrees and damp. I had worn light long underwear and a hat. That was enough, as I had stayed comfortable and slept well. There was no cold intrusion around the neck yoke or through the down and only a little slipped past the zipper baffle when I pressed against it. It could have easily been a miserable night, but the Magma performed like a champ.

Everything got packed up damp again and I hiked on past the amazing cliffs that the park is named for. By early afternoon the rain had quit, the sun started to show, the temperature climbed and for all practical purposes, this test was complete.


Grand Portal Point

  • Manufacturing quality was high, with no noticeable sewing defects.
  •  Impressive design touches such as the neck yoke, no stick zipper and adjustable hood.
  • For me at least, the bag hits the temperature rating under tough conditions. Not every bag has. (Once you go below 40 or so, with any bag, an insulated pad becomes crucial.)
  • The bag is light for the temperature rating without resorting to a tight fit.
  • The bag has the certifications to show environmentally responsible manufacture.
  • While not cheap, the price is in line with other bags of this quality. In addition, REI will put this bag on sale at times.


Stuff sack and larger mesh storage bag are included with the purchase price.

The provided stuff sack is almost comically small. Yes, you can use it. However, if you do, you will like this bag a lot less. It does show that the bag is extremely compressible though.

The Verdict

Magma 30 stretched out in the tent under relatively pleasant conditions.

The REI Magma 30 is a great, lightweight bag that can be used from shoulder seasons through the summer. For those on long distance hikes, this one bag could be a simpler answer than two bags that have to be switched out, hopefully at the right time.

High quality, warm and comfortable under tough conditions. That’s what I hope for in a sleeping bag and the REI Magma 30 delivered. Considering the superior manufacturing, well thought out features and the high quality of the down, the bag seems to be priced very fairly. Get yourself a six liter or so stuff sack to go with it and the world will be a better place.

Shop the REI Magma 30 Here

This item was donated for purpose of review 

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Comments 3

  • Backpack Sac : Aug 18th

    I recently bought this bag, and have no issues with the stuff sack. I just start with a small portion of the sleeping bag in the stuff sac, press that down to compress it, and repeat that 7 or 8 more times until the back is stuffed. I even have enough room to put my deflated air pillow in the opening of the sac (that way, they’re both together). Again, no issues with the stuffing . . . . just take it in steps.

    Allen, Sacramento, CA, USA

  • Riya Sen : Aug 18th

    I’m really excited to try out the REI Magma 30 sleeping bag! I’ve been looking for a good sleeping bag that is lightweight and warm for backpacking.

  • Zaphyzen : Oct 28th

    Thanks for the nice review. I bought this bag for $86 on sale and am looking forward to using this.


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