Backpackers, thru-hikers, and mountain runners all want to thread the needle and find the right ultralight rain jacket for their respective missions. You can get all the way down to the 4- to 5-ounce range for the most minimalist and streamlined of shells, but there are important considerations, including breathability, weather protection, durability, features, cost, and more. Below, we dive deep into the ultralight shell market in 2026 and break down the key models.
Tips the scales at: 5.7 oz. (men’s), 5.6 oz. (women’s)
Shell: 2.75-layer Toray Dermizax, 15D
What it is: Superlight, well-built, and surprisingly comfortable.
What it isn’t: Breathable, durable, or feature-rich.
The Helium UL is the O.G. of ultralight rain jackets, now with modern twists. Seattle-based Outdoor Research originally debuted the Helium line all the way back in the spring of 2010, and over a decade and a half later, it’s still one of the lightest rain jackets you can buy. At a scant 5.7 ounces and with a tiny packed size (the Helium stuffs into its lone chest pocket on the men’s version or the left-handwarmer pocket on the women’s), it’s easy to jam into your pack, vest, or outer stretch pocket. For just about any mountain adventure, including ultralight backpacking, mountain running, or day hiking, it’s a jacket that many people frequently turn to.
We didn’t love the slippery inner layer on the original Helium, which didn’t breathe well and felt clammy. Now, with a Toray Dermizax 2.75-layer construction—the “.75” part of that equation is a printed inner lining—the Outdoor Research Helium UL is improved on the breathability and comfort front but remains an emergency shell at heart. In this regard, it falls well short of more premium 3-layer shells featuring highly protective Gore-Tex membranes and moisture-wicking liners. Notably, it also lacks pit zips, core vents, or other ventilation options, so once you start moving, moisture can build up quickly.
In terms of durability, the relatively thin 15-denier shell means that you’ll have to take due care with the Helium UL. This is par for the course with ultralight rain jackets in general, as using thin fabrics is the primary way to drop ounces. Outdoor Research also skipped hand pockets on the men’s version of the Helium UL, featuring instead only a single zippered chest pocket (the women’s version still gets two zippered hand pockets), though they didn’t skimp on the hood, with solid adjustability and a wire brim.
In the end, we’d recommend the Helium UL for on-trail hikers and backpackers, ideally in cooler climates who won’t be pressing too hard for extended periods while wearing it. It’s a superb ultralight emergency shell if you keep it in its lane, and the latest version is less shiny and techy-looking than before, so it can crossover to urban uses like travel and commuting. But for heavy aerobic activity or all-day wear, you can find a better match.
Tips the scales at: 6.3 oz. (men’s), 5.7 oz. (women’s)
Shell: 3-layer Super Dry-Tec, 7D
What it is: Ultra thin, more breathable than the Helium (including pit zips) with only a tiny weight penalty.
What it isn’t: Tough (it’s quite the opposite) or as weather protective as Gore-Tex.
If the Helium UL has limitations, the Versalite addresses many of them. For $65 more, you get a notable step up in breathability with a 3-layer Super Dry-Tec shell, and more features, including the ever-important pit zips for dumping heat. This combination gives the Versatile much less of that plastic-bag-like feel and can allow you stay sane while moving fast in the backcountry.
To achieve this added functionality while weighing just 0.6 ounces more than the Helium, Montbell, you guessed it, thinned the shell fabric out even more. The Versatile has a fragile 7-denier nylon ripstop shell, which is the thinnest you’ll find in this category (they follow the same route with their 7-denier Plasma 1000 down jacket, which offers incredible warmth-to-weight). Going truly minimalist has its compromises, and you will realistically have to baby the Versatile to keep it in use and performing for the long haul. You also give up storage: both the men’s and women’s versions are pocket-free (a separate stuff sack is included).
A couple more things to keep in mind with the Versatile: Despite the 3-layer build, Montbell’s Super Dry-Tec is not Gore-Tex. It does a good job at protecting you from the elements during light to moderate precip, but all-day outings in super wet conditions will put it to the test and may lead to wetting out (this can happen with any rain jacket, but Gore-Tex is king in the gnarliest of conditions). Second, Montbell’s fit is unique. The company is based in Japan, and on the U.S. site, it does offer “Western Sizes,” but one of our editors with a long, lanky torso can never find the right size from Montbell. Even the Western Sizes tend to favor normal-to-short builds rather than those with broad shoulders and long arms.
To wrap, grab the Versatile if you value breathability and the ability to dump heat via the pit zips. Given the super-thin shell, it’s not the best ultralight rain jacket for off-trail ventures and bushwhacking, or for people who are hard on their gear in general.
Tips the scales at: 8.2 oz. (men’s), 6.5 oz. (women’s Anorak)
Shell: Gore-Tex Pro ePE, 20D
What it is: Pretty much the whole package in a lightweight shell, and good in the wind.
What it isn’t: Cheap or as light as the options above.
Here is where things truly get fun, but we’ll start with the downsides this time to temper our enthusiasm. The Arc’teryx Alpha SL costs a whopping $500 (more than double the price of the Helium UL) and weighs a couple of ounces more than either of the options above. For true ounce counters and those only planning on using their rain jacket in an emergency downpour, it’s overkill to be sure. But for those who really depend on the rain jacket and plan on wearing it for extended periods of time in all kinds of conditions, the Alpha SL is the real deal and Arc’teryx’s lightest alpine shell.
Among other things, the big jump up here is to Gore-Tex Pro ePE. If you don’t know, Gore-Tex was invented in the 1960s and has been the market leader in waterproofing pretty much ever since. Yes, Gore-Tex costs more than in-house alternatives, but it backs it up on the performance front. Over the years, we’ve tested just about every proprietary waterproof membrane out there, and while many are decent and some border on impressive (especially for the price), none do the job quite like Gore. It’s also important to note the “Pro” construction of the Alpha SL, which signifies the brand’s pinnacle of protection and toughness.
The result is a rain jacket (a hardshell to be exact) that is still impressively lightweight—half a pound for those counting at home—offers superior wet-weather protection compared to the jackets above, and is more breathable, although it does not come with pit zips. Importantly, the Alpha SL has a 20-denier Hadron shell fabric, making it substantially tougher than the Montbell and other sub-10-denier models. It’s also worth noting that the thicker shell also helps in windy conditions and can even offer a little bit of insulation on chilly days.
To sum it up, the Arc’teryx Alpha SL is a superb ultralight rain jacket for alpine/tough environments. If you are heading to the mountains in the summer months and rain isn’t much of a concern, an emergency shell like the OR Helium UL or Montbell Versatile should do just fine. But for places like Patagonia, Norway, Alaska, or Wyoming, a hardshell becomes a necessity.
And a final love letter to this jacket: I’ve been testing gear for way too long and have an extensive gear room. If I had to pick three gear items and you took all the rest, my past-generation version of this jacket (by a different moniker, as Arc’teryx changes those frequently) would definitely make the cut. I recently had it re-DWR’d by Arc’teryx and spent a full 12 hours out in the Weminuche Wilderness on a terribly rainy day (sustained downpours, all day, dawn to dusk). Not a drop of water made it inside, and we were bushwhacking much of the day. You’d have to pry that jacket from my cold, dead hands. If you really use it, it’s worth the $500.
Into the Thru-Hiking Den…
Few count ounces like thru-hikers, so it’s an interesting world to jump into. Unfortunately, we are going to hold off covering the Enlightened Equipment Visp, which was a thru-hiking staple for years, at 5.6 ounces for a medium. All sizes are currently out of stock on the company's site, and it’s not listed in its apparel section (RIP Visp?... that’s a bummer). At least they still make the Torrid.
If you look at Halfway Anywhere’s annual PCT Thru-Hiking survey, which is a fun way to get into the heads of all of those PCT’ers, the most common rain jacket used was the Frogg Toggs Ultra-Lite 2 Rain Suit (this is not a misprint). For $33 total for the jacket and pants (again, not a misprint), you get what they call a waterproof setup that weighs around 21.6 ounces combined. On the site, Frogg Toggs lists the pants as 12.8 ounces and does not list a jacket weight, but the Ultralight Jacket (version 1) is listed at 8.8 ounces. We get it: Thru-hiking is expensive, and the PCT starts in Arizona, and most move up to the Pacific Northwest during the summer months. But ironically, that same Frogg Toggs setup is the lowest-rated shell of all in that same survey. As my mammy says, “You often get what you pay for.” In terms of the highest rated, the people have the Montbell Versalite #1.
What About the Patagonia Torrentshell?
A final note on the PCT survey: The Patagonia Torrentshell 3L is the third-most common shell and the third-highest-rated. The Torrentshell is a great all-around rain jacket, featuring a 3-layer H2No build (Patagonia’s proprietary waterproofing is among the best non-Gore-Tex options out there). It has a bunch of features, including pit zips, hand pockets, and a burly 50D nylon fabric, which sounds very reassuring after reading about the jackets above. But the Torrentshell isn’t very compressible and weighs 14.1 ounces, which is not ultralight in our book.
We understand why people would choose the Torrentshell: It’s dependable, tough, easy to wear for extended periods, weighs less than a pound, and costs less than anything above at $189 (even the Outdoor Research Helium UL is $220). Plus, many hikers and backpackers may already have this rain jacket as it's uber-popular and you’ll see it all over town. If you aren’t counting ounces (the Torrentshell is realistically more than twice the weight of the OR or Montbell), it’s a nice all-rounder—just far from the lightest. To read about the Torrentshell more in the context of the entire category, see our guide to the best rain jackets.
Running-Centric Ultralight Shells
When you get into the world of mountain running, the gear can get pared down even further. The Rab Phantom ($225) weighs an incredibly low 4.1 ounces and features a 7D Pertex Shield 2.5-Layer build. This outer fabric is as thin as the Montbell Versalite (making it tied for the thinnest jacket mentioned in this article), but it is even more pared down, with a thinner lining, no pit zips, minimalist elastic cuffs, a partially elasticated hem, and a non-adjustable hood. The cut also appears quite short, ending right around the waist. Rab bills the Phantom as being built for “ultra running, mountain races, and thru-hiking,” so there you have it. We have the Phantom out for testing this spring and want to gauge the quality of its waterproofing in particular, but you won’t find a more minimalist (or lighter) option.
Last but not least, Patagonia quietly has its own streamlined mountain-running jacket, the Storm Racer ($315). At 7.2 ounces for the men’s version (6.3 ounces for the women’s), it’s quite a bit heavier than the Rab Phantom, but about half the weight of the aforementioned Torrentshell. The jacket has a 20-denier, 3-layer H2No shell, so it’s right in the range of the Arc’teryx Beta SL in terms of thickness, which is a sweet spot of protection, toughness, and packability, in our opinion. It has no vents or pockets, though you do get a hood toggle, which is nice. If you like Patagonia jackets but the Torrentshell is too heavy and feature-rich, the Storm Racer is an intriguing option, although you do pay for the privilege.
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