Name: Rab Mythic G
Brand: Rab

The Rab Mythic G delivers outstanding warmth given its ultra-lightweight design. The hoody is stuffed with 4.5 ounces of super high-end 1,000-fill down in a men’s medium (the down accounts for more than half of its total weight of 9.8 oz.), and also features a heat-reflective lining. I felt the warmth immediately upon putting the jacket on, and this puffy kept me warm as part of my layering system on a four-day backpacking trip in Washington’s Goat Rocks Wilderness as well as a five-week expedition to climb 13,186-foot Mount Waddington in British Columbia, both trips where minimizing weight and bulk makes everything better. I was especially glad to have the Mythic G with me during an unplanned bivy at 9,000 feet in the Washington Cascades—temps dipped to the high 30s, and while I was a bit chilly, I remained comfortable enough.

The bottom line is that the Mythic G is a toasty down jacket, and I would confidently rely on it for cold-weather hiking, climbing (as a belay or emergency piece, given its low durability), and ski touring. Around camp, when I’m more stationary, I found it sufficiently warm down to the low 20s (it’s worth noting I run warmer than average). The Mythic G provides similar warmth to my heavier Rab Electron Pro (1 lb. 2.5 oz.), and more warmth than my old Patagonia Down Sweater Hoody (read our Down Sweater review), which weighs 14.8 ounces. At under 10 ounces, that’s truly exceptional performance.

enjoying dinner while the sun goes down in Rab Mythic G Down Jacket

This is where the Mythic G truly shines—it’s rare to find a down jacket this warm that’s also this light and packable. At 9.8 ounces for a men’s medium (10 oz. on my scale), the Mythic G is among the lightest puffies in the category, and thanks to the high-end, 1,000-fill-power down, it compresses down to smaller than a 1-liter Nalgene in its included stuff stack. Over the course of my testing trips, that packability was much appreciated when I didn’t need the extra warmth. The mix of warmth, lightness, and compressibility is exactly what you’d want for the backcountry, especially regions with long approaches such as the Cascades.

Even when compared to other ultralight jackets, the Mythic G still stands out for its balance of warmth and weight. The Ghost Whisperer, although an ounce lighter than the Mythic at 8.8 ounces, provides notably less insulation (3 oz. of 800-fill down and no heat-reflective lining). It’s a similar story for the Arc’teryx Cerium Hoody (reviewed here), which weigh two ounces more than the Mythic, but we’ve found it only warm into the low 40s or upper 30s Fahrenheit, whereas the Mythic is comfortable in below-freezing temps. (That said, both competitors cost significantly less.)

I think it’s uncommon to find a lightweight down jacket that’s not comfortable, but even still the Rab Mythic G rates highly amongst its peers in this category. The interior liner is soft despite its heat-reflecting quality and metallic look, and there’s a comfortable microfiber patch at the collar where the jacket zips over your chin. Fit-wise, the Mythic G’s regular cut is roomy and unrestrictive without seeming bulky, and it feels featherlight on my shoulders.

Unsurprisingly, since the Mythic G prioritizes lightweight warmth, its 7-denier (D) face fabric is quite thin. While most everyday down jackets fall in the 20D to 30D range—the Patagonia Down Sweater and the Stio Pinion are 20D, and even famously lightweight models such as the Mountain Hardwear Ghost Whisperer are usually 10D to 15D—I’ve had to be extra careful around sharp branches, rocks, and gear with this puffy. This is not a jacket for rugged use, but that’s the tradeoff for its minimalist appeal.

Otherwise, this jacket demonstrates long-lasting build quality in the details, with excellent stitching and smooth zippers. During 30 days of testing, a few feathers escaped the jacket, which is comparable with other puffies I’ve owned. The Mythic G’s quality matches expectations for a top-of-the-line—and top of the price sheet—puffy.

The Mythic G seals out moderate wind, but it performs poorly in rain. Despite its durable water-repellent coating (DWR), the thin face fabric wets out quickly, and the jacket will almost immediately absorb water. I wouldn’t trust this puffy in any kind of precipitation; since down loses its ability to insulate when wet, a shell will be necessary if you’re facing rain or snow. (The Mythic G’s down has a hydrophobic coating, but it doesn’t hold out for long.) On the plus side, the elastic cuffs and adjustable hem effectively block out cold drafts.

In comparison, many down jackets will at least bead water for 20 minutes in misty conditions. For instance, the Cerium Hoody’s water resistance can handle light drizzles for over an hour, and with synthetic insulation in moisture-prone areas, it also more effectively maintains warmth when damp—but those upgrades come at the expense of more weight.

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Longevity

Choosing durable outdoor gear is perhaps the most effective way to reduce environmental impact—the longer it lasts, the less it needs to be produced. Our proprietary longevity rating evaluates overall build quality based on factors such as materials, fabric denier, component durability (including zippers and toggles), real-world performance as reported by our field testers, and our experiences with the brand.

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Hood
The hood on the Mythic G is another thoughtfully designed highlight. It has a great fit with enough stretch to fit over a helmet, yet it’s not bulky or oversized without one. The hood opening features elastic at the sides, while the top and chin areas are non-elastic (the top has a wire-like brim that slightly increases coverage). Despite a lack of adjustability, this design creates a snug fit, preventing drafts from coming through. Finally, there is a fleece-lined chin guard at the top of the zipper, adding a soft next-to-skin feel.

closeup of Rab Mythic G Down Jacket's hood and collar

Storage
You get two standard hand pockets on the Mythic G, each with smooth-running, concealed zippers that add to the jacket’s premium look. Each pocket provides plenty of room for a phone, lightweight gloves, or a pocket camera. Notably, in keeping with its ultralight design, the jacket lacks a chest pocket or internal drop-in pockets.

keeping hands warm in Rab Mythic G Down Jacket's pockets

Tester: 5’8” 140 lb.; 38" chest; 28" waist

Size tested: Men’s medium

I typically wear men’s size medium down puffies, so I tested the Rab Mythic G in a medium as well and found that it fit as expected. With my body proportions—I have a long torso, wide shoulders, and short arms relative to my height—I often have issues finding jackets that are long enough without being too large in the trunk or overly long in the sleeves. I encountered these same issues with the Mythic G: The jacket was an appropriate length and fit well in the shoulders, but the torso felt loose, and the sleeves were a bit long. On the plus side, between the loose fit and articulated sleeves, I enjoyed unrestricted range of motion. Although I usually prefer a slimmer, more athletic cut, especially for climbing, I believe that most people will find that the Mythic G offers a comfortable fit.

Man looking at mountains wearing Rab Mythic G down jacket

Mountain Hardwear Ghost Whisperer Hoody ($360): For Mild Conditions
The Mountain Hardwear Ghost Whisperer is one of the most popular ultralight down jackets for summer backpacking and other weight-conscious adventures in mild weather. It’s an ounce lighter than the Mythic G, but packs in noticeably less insulation (3 oz. of 800-fill down compared to the Rab’s 4.5 oz. of 1,000-fill down). We recommend it for temperatures as low as 50 degrees Fahrenheit (potentially colder if you’re moving), and it’ll save you $165, too. However, if you need a jacket that will keep you warm in below-freezing conditions, the Mythic G is hard to beat. For more, read our review of the Mountain Hardwear Ghost Whisperer Hoody.

Arc’teryx Cerium Hoody ($400): Added Weather Protection for Less Money
The Arc’teryx Cerium Hoody doesn’t offer quite the warmth of the Mythic G, and it’s 2 ounces heavier, but it’s a better value thanks to a lower price tag and more durable face fabric. For $125 less, the Cerium contains 4 ounces of 850-fill down, plus synthetic insulation in moisture-prone areas like the collar and under the arms. It’s hard to do the math when comparing different fill weights and synthetic vs. no synthetic fill, but in practice, the Cerium is warm into the low-40s/upper-30s, while the Mythic G’s temperature range extends below freezing. If you have the cash, the Mythic is still the most intriguing ultralight choice for cold and dry conditions. But if you want to save or need the added protection from moisture, the Cerium Hoody is a solid pick. For more, read our review of the Arc'teryx Cerium Hoody.

Rab Mythic G ($525)

cooking dinner in Rab Mythic G Down Jacket

4.4/5

Hold up, what!? We can’t believe Rab managed to pack this much warmth into such a lightweight jacket. You’ll pay a pretty penny for it, and it's unsurprisingly fragile. But the Mythic G is the only sub-10-ounce jacket we know of that can handle freezing temperatures.

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Weight

9.8 oz.

Insulation

4.5 oz. of 1,000-fill down

Fabric

7D nylon

Packable

Yes (stuff sack)

Warmth

3.5/5

Weight & Packability

4.5/5

Comfort

4.5/5

Durability

1/5

Weather Resistance

2/5

Sustainability

3.8/5

Mountain Hardwear Ghost Whisperer Hoody ($360)

Hiker wearing Mountain Hardwear Ghost Whisperer Hoody down jacket

4.6/5

The Ghost Whisperer is one of our favorite ultralight down jackets, with a low weight and small packed size. Despite its streamlined feature set, it's versatile in the mountains, and the attractive, low-profile fit crosses over well for casual environments and mild weather. However, the thin fabric is fragile and requires care.

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Weight

8.8 oz.

Insulation

2.4 oz. of 800-fill down

Fabric

10D nylon

Packable

Yes (pocket)

Warmth

2/5

Weight & Packability

4.5/5

Comfort

4.5/5

Durability

1.5/5

Weather Resistance

1.5/5

Sustainability

2.9/5

Arc'teryx Cerium Hoody ($400)

Woman standing on rocks wearing Arc'teryx Cerium Hoody down jacket

4.7/5

The Cerium offers extremely lightweight and packable warmth for technical pursuits like alpine climbing and backcountry skiing. Its streamlined fit is ideal for layering, too. However, given the price point, thin fabrics, and trim fit, we don’t recommend this jacket for everyday use.

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Weight

11.9 oz.

Insulation

4.0 oz. of 850-fill down + synthetic

Fabric

15D nylon

Packable

Yes (stuff sack)

Warmth

3.5/5

Weight & Packability

4/5

Comfort

4.5/5

Durability

2/5

Weather Resistance

2.5/5

Sustainability

4.4/5

Is the Mythic G for You?

Your wallet will no doubt feel much lighter if you buy the Rab Mythic G, but so will your pack. Offering maximum warmth and comfort for its minimal weight, this jacket is a great choice if you’re counting ounces on trips into the alpine where the temps will dip towards (and possibly under) freezing. If you’re a weight-conscious climber, skier, and fastpacker, put this one on the ol’ dream list—it’s a true technical tour de force with super-premium 1,000-fill-power down and a functional heat-reflective lining. But for casual or mild-weather outings where weight is less of a concern, we’d opt for a more traditional down jacket (think Patagonia Down Sweater) that offers more durability at a much lower cost.