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Arc'teryx Sigma SL Anorak Pullover - Women's Review

This lightweight and streamlined pullover is a fabulously durable layer that breathes like a dream and dries lightning fast
Arc'teryx Sigma SL Anorak Pullover - Women's
Editors' Choice Award
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Price:  $189 List | Check Price at REI
Pros:  Highly breathable, quick-drying, foam inserts prevent jacket creep, helmet compatible, stowable hood, durable
Cons:  Not very warm, no stow-away pocket for clipping to your harness, cuffs stretch out with heavy use
Manufacturer:   Arc'teryx
By Mary Witlacil and Penney Garrett  ⋅  May 7, 2020
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  • Weather Protection - 30% 8.0
  • Breathability - 30% 8.0
  • Mobility - 25% 9.0
  • Weight - 10% 8.0
  • Versatility - 5% 7.0

Our Verdict

The Arc'teryx Sigma SL Anorak Pullover dazzled our reviewers nabbing our coveted Editors' Choice award, yet again. This wind-resistant active softshell earned top-ratings in nearly all of our testing criteria: it's highly breathable and lightweight, offers great weather protection for an active softshell, moves like silk, dries fast, is wicked feature-rich, and decently versatile. This jacket is our go-to softshell for rock climbing of all persuasions: from windy multi-pitches, and alpine climbing to breezy days clipping bolts. We even loved this jacket for early morning hikes, trail runs, and fair-weather backpacking. The material is durable and protective without feeling stiff or scratchy on bare skin — indeed, it is our go-to skin-saver in off-widths and chimneys. If you want something to take on all your warm-weather activities, we highly recommend the Sigma.

Our Analysis and Test Results

It is no wonder that the Sigma SL Anorak stole the show. This dope layer balances wind-protection with breathability like a dream. It is feather-weight with just enough features, comfortable and moveable but also abrasion-resistant and durable, and it looks good to boot.

Performance Comparison

This pullover is ideal for almost any swing season activity.
This pullover is ideal for almost any swing season activity.
Credit: Scott Sinor

Weather Protection

Being an active softshell, the Sigma SL is not designed for winter conditions or seriously inclement weather. That said, it provides considerable wind protection and water resistance in a light drizzle.

The Sigma offers great weather protection for an active softshell, being as wind-resistant as they come (without being wind-proof). When coupled with a lightweight fleece, like the Patagonia R1, it is sufficiently warm into fairly low temps — as long as you are moving. In our water-resistance tests, the Sigma was in the middle of the pack. This means that while the Sigma is not an ideal layer to keep you dry in a deluge, it provides some water resistance in light rain or dry snow. As an alpine climbing layer, the Sigma is great for days when meteorologists predict low-levels of precip. Even on those days, we always bring a lightweight rain jacket like the Outdoor Research Helium II for unexpected weather emergencies (especially in the unpredictable Rocky Mountains). Rest assured, if you do get caught in a storm, the Sigma dries almost supernaturally fast. With the breathable nature of the fabric, (a tightly woven proprietary material called Aequora Airperm), this is also a great piece to use as a sun layer when you don't want to get scorched. Finally, while the Sigma is not meant for super cold temps, the slim cut means it's easy to layer under or over something more substantial if needed.

The Sigma is highly breathable and wind-resistant, even while...
The Sigma is highly breathable and wind-resistant, even while climbing on warm but breezy days in Eldorado Canyon.
Credit: Scott Sinor


The Sigma SL breathes well during cardio-intensive activities and warmer days, and if you need more ventilation, it features a deep front zipper for extra air-flow. While some folks will find it suitable for things like trail running on cooler days, it's better suited for slightly slower-paced activities like climbing or hiking.

This pullover offers an impressive trifecta of breathability, protection, and quick-drying material. Whether it's super sunny or you're working up a sweat (or both!), you won't feel overly stifled, and wet spots will dry fast. Magically, when a crisp breeze rolls in, you'll also feel protected. It's kind of amazing that one layer can handle so many different scenarios so well. This is why we love the Sigma for climbing almost year-round (if you're lucky enough to have access to sunny crags in the winter). It handles quick changes in sun, wind, and body temp.

Climbing multi-pitch routes in Eldorado Canyon in early spring often...
Climbing multi-pitch routes in Eldorado Canyon in early spring often entails rapid changes in temps, when a breeze picks up or the sun moves behind a cloud. The Sigma handles all these temperature changes with ease.
Credit: Scott Sinor


Mobility is really where the Sigma shines. It is made out of a lightweight four-way stretch material that is highly abrasion-resistant and easy to move in, you'll be happy in this layer whether you're having a spontaneous backcountry dance party or swimming up desert cracks.

At first touch, the material doesn't feel overly stretchy, but once on the body, it moves fluidly and gracefully. The slim cut means it stays close to the body and out of the way without being constrictive. Really though, the most innovative aspect of this pullover is the proprietary "Hemlock" (foam) inserts in the hemline — these rad little buddies keep the jacket locked in place under your harness. Never again will you have to wrestle with your jacket to hide climber's crack from your belay partner. Phew. Beyond this, the hood has a button to roll it up and stow it away if you don't want the extra material hanging behind you. The only reason the Sigma did not earn a higher score in this category is that the stretchy nylon in the cuffs stretched a bit too much with heavy usage. This is not a deal-breaker, but the sleeves did feel noticeably loose around the wrists when reaching for high handholds after a couple months of hard use. That said, it's still an incredibly mobile and cozy softshell that we love for protecting our skin in off-widths and chimneys.

Stretchy and expertly tailored, the Sigma is a delight to climb and...
Stretchy and expertly tailored, the Sigma is a delight to climb and move in.
Credit: Penney Garrett


The Sigma has an "SL" designation, which stands for "super light" — at just 9.5 ounces for a size small, it certainly is!

This Sigma is lightweight and incredibly packable, though it would be even more packable with a stow-away pocket for clipping on to your harness. This minor drawback aside, when you couple the Sigma's featherweight with incredible durability, you get a fantastic alpine climbing layer. Even when your pack is stuffed to the brim with climbing gear, there's always a fragment of space to cram this jacket. You'll be glad you did.

Our lead reviewer rocking an older generation of the Sigma on the...
Our lead reviewer rocking an older generation of the Sigma on the summit of Longs Peak.


With excellent features and fantastic breathability, mobility, and weather-resistance, this savvy pullover is pretty darn versatile.

The Sigma shines in fair but breezy weather, or when in a light summer rain. It handles wind like a boss, making it an incredible wind layer for multi-pitch and alpine climbing, hiking, light mountaineering, or peak-bagging. When used with a light fleece, the Sigma can handle breezy and cooler days in the spring and fall, as well as alpine starts in the summer. It is the most durable jacket in our review, making it an ideal layer for abrasion resistance in granite chimneys and off-width. It is fitted, attractive, has a spacious helmet-compatible hood, and with the foam inserts in the hem, it resists jacket-creep while climbing. The hem-cinch is somewhat complicated to undo, but with the Hemlock inserts, it is unnecessary when under a harness. You can zip the Sigma up to the chin for extra warmth or vent it down to your belly-button for extra air-flow. If you're looking for a three-season, wind-resistant jacket for rock climbing of all persuasions, then this little gem might be right for you.

Click to enlarge
Click to enlarge
Click to enlarge


While the Sigma certainly is not one of the least expensive jackets in our review, it is decently affordable. If you're looking for an ultra-durable, lightweight, fast-drying, and wind-resistant climbing layer, this jacket certainly checks all those boxes and more. Considering how high-performing and feature-rich it is, the price seems well worth what you get. If you're down to foot the bill, you will be pleased you did, as this jacket will prove its worth nearly every time you head out to climb.

The Sigma is so lightweight that you'll forget you were wearing it...
The Sigma is so lightweight that you'll forget you were wearing it, so you can focus on finessing your footwork.
Credit: Scott Sinor


The Sigma SL Anorak is a lightweight technical softshell geared toward alpine rock climbers. Don't let that turn you away if that isn't what you do — this well-designed pullover is a fantastic layer for a number of other activities too. It's incredibly breathable, stretchy, durable, weather-resistant for its weight, and crazy quick-drying. Bottom-line, the Sigma is a fantastic layer for all manner of outdoor pursuits from hiking, running, and bike commuting to peak-bagging, fair-weather backpacking, and canyoneering. We think you'll be as psyched as we were to give this Editors' Choice Winner a try.

With four-way stretch and the Hemlock inserts in the hemline, the...
With four-way stretch and the Hemlock inserts in the hemline, the Sigma topped the charts in multiple metrics. Proving to be an all-around fantastic jacket for climbing.
Credit: Scott Sinor

Mary Witlacil and Penney Garrett
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