Review: Rab Mythic Alpine Down Jacket

Water-Resistant Down Jacket
Rab Mythic Alpine Down Jacket
$390, 11 oz./313g (men’s medium)
Sizes: men’s S-XXL, women’s XS-XL

A weeklong backpacking trip in Glacier National Park in mid-September presented a quandary: Starting out with the weight of a week’s food gave me added incentive to trim all superfluous weight from my pack; yet the possibility of temperatures dropping near or even below freezing made bringing adequately warm layers essential. The Rab Mythic Alpine Down Jacket achieved both goals, keeping me warm on our coldest mornings in Glacier while weighing less than most comparably warm puffy jackets.

In Glacier, I wore it over just two light base layers except when the temperature dropped below around 40° F/4° C, when I added a light fleece hoody. The Mythic Alpine also provided enough warmth over just one or two base layers on cool nights in early October backpacking the 22-mile Boulder Mail Trail-Death Hollow Loop in southern Utah’s Grand Staircase-Escalante National Monument and nights in the upper 30s Fahrenheit (around 3° C) while camping at Idaho’s City of Rocks National Reserve in June.

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The Rab Mythic Alpine Down Jacket.
The Rab Mythic Alpine Down Jacket in Glacier National Park.

The explanation is simple: This fat puffy is stuffed with 4.9 oz./140 grams of RDS-certified, hydrophobic, 900-fill goose down (for the men’s medium), giving it one of the highest warmth-to-weight ratios you’ll find in a down jacket, as well as making it very packable. The jacket comes with a stuff sack and packs down to the size of a small camping pillow—compact enough to keep near the top of my backpack and pull on during breaks in chilly wind.

The jacket’s hydrophobic down enables it to retain its loft and ability to trap heat even when damp and dry faster than standard down. That quality further sets the Mythic Alpine apart from competitors as a water-resistant down jacket with a very high warmth-to-weight ratio.

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The Rab Mythic Alpine Down Jacket.
The Rab Mythic Alpine Down Jacket.

The adjustable hood has a slight brim and, with a single drawcord in the back, it snugs smoothly around your head, delivering a noticeable boost in warmth. The front zipper extends up over your chin, sealing in warmth effectively, as do the elasticized cuffs and adjustable hem. Two zippered hand pockets provide warmth for hands and for stashing three-season gloves or items of similar size.

At 11 oz./313g (men’s medium), it’s a lightweight among insulated jackets. And its premium-quality down makes it warmer than other hooded jackets at the same weight but with a lower down-fill rating.

Perhaps most distinctively, it’s warm enough for temperatures down to just above freezing when paired with the right layers—making it one of the lightest down jackets that can handle most three-season trips. 

The slim fit allows wearing a couple of light layers and even a thin fleece underneath and it comes in five sizes each for men and women. It also layers easily under most backcountry rain shells.

To help keep weight at a minimum, this puffy uses an ultralight, windproof, 10-denier ripstop, 100 percent recycled Pertex Quantum shell fabric with a fluorocarbon-free DWR(durable, water-resistant finish)the lightest shell fabric used in insulated jackets. It will provide adequate durability for a down jacket as long as you exercise reasonable caution with it. I’ve seen just a few single feathers leak out in numerous days wearing it. Of all materials used in the jacket, 39 percent are recycled, according to Rab.

The stitch-through baffle construction, which stitches the outer, shell fabric to the inner, liner fabric—commonly used to reduce a jacket’s weight and often the cost—creates boxes of down with potential cold spots at seams separating them. But I noticed no negative impact on warmth even on chilly, windy evenings and mornings in camp.

Rab also offers an even lighter but otherwise identical version, the Mythic Alpine Light Down Jacket ($330, 8.8 oz./252g), best for milder temps, in the mid-40s F (about 7° C) or higher.

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The Verdict

With water-resistant, 900-fill down, and one of the highest warmth-to-weight ratios found in any down jacket, the Rab Mythic Alpine Down Jacket represents one of the lightest and most packable and versatile puffy jackets that’s warm enough for most three-season trips.


You can support my work on this blog, at no cost to you, by clicking any of these affiliate links to purchase a men’s or women’s Rab Mythic Alpine Down Jacket at or or a men’s or women’s Rab Mythic Alpine Light Down Jacket at or

For a warmer and less expensive, water-resistant down jacket, that’s also heavier and is stuffed with medium-quality 700-fill down, see my review of the Rab Microlight Alpine Down Jacket ($280, 15 oz.).

See “The 12 Best Down Jackets” and all reviews of insulated jackets and outdoor apparel at The Big Outside.

NOTE: I tested gear for Backpacker Magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See categorized menus of all of my gear reviews at The Big Outside.

—Michael Lanza

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