The Gamma LT Hoody is well-tailored and moderately feature-rich, providing an excellent layer for aerobic activities in swing season temps. Stellar mobility and breathability combine with durable fabric, harness-friendly pockets, and a helmet-compatible hood, for a rad alpine adventure jacket.
Performance Comparison

The Arc'teryx Gamma LT is perfect for an aerobic hike in the alpine on a classic fall day where you have sun, wind, and temperatures varying from quite chilly to mildly warm.
Photo: Penney Garrett
Weather Protection
The Gamma LT didn't receive the highest score in this category due to being made from a lightweight and ultra-thin material. While it's an impressive shell all around, when stacked up against some of our thicker, more insulative models, this one isn't quite as warm. "LT" is the shorthand Arc'teryx gives to lightweight items, and they recommend this jacket in particular for alpine and backcountry excursions. We agree with this designation, though if the weather turns on you, you will be cold if you're not moving. But if the weather stays relatively temperate and you're staying active, we predict you'll be happy as a clam (though not as clammy).

The Gamma LT Hoody is brilliant for cooler days and aerobic activities.
Photo: Penney Garrett
While the Gamma LT is thin enough to let some wind and cold through, the patented Wee Burly Double Weave fabric and DWR finish is notably impressive for keeping water out. We wore each jacket into the shower to see how long it could repel an intense dousing, and the Gamma LT was one of the more impressive performers, resisting total failure like a boss.

This lightweight durable shell was notably impressive when it came to repelling water. Here you can see how it just sits on the surface and doesn't soak in at all.
Photo: Penney Garrett
Breathability
The Gamma LT excels in this metric, providing some of the better breathability in our review. From climbing in the sun and alpine starts, to early morning trail runs and high altitude snow hikes in variable temperatures, this layer keeps you protected but not stifled. The pockets are also mesh-lined, for when you need some added ventilation.

If aerobic swing season activities are your jam, the Gamma LT is a fabulous choice.
Photo: Penney Garrett
Mobility
This jacket is a rad option for mobility. It's constructed with stretchy fabric and has gusseted underarms and an athletic fit — a pretty winning combination for movement. No matter what activity we undertook in the Gamma LT, it moved and stretched easily and naturally. We especially love how comfortable it is to climb in, never feeling cumbersome or bulky.

Having full range of motion in your softshell is extremely important in order to stay protected without feeling uncomfortable or impeded.
Photo: Penney Garrett
Weight
At 15.3 ounces for a size medium, this is a moderately heavy layer — our review contains quite a few lighter options. However, this is still a great shell to consider if you want to stay relatively light but desire a lined softshell for extra warmth, and want greater durability out of your softshell.

The Gamma LT strikes a great balance between weight and burliness. It's a smart layer to take traveling in mild temps because it will provide good protection without weighing down your suitcase.
Photo: Penney Garrett
Versatility
In most respects, the Gamma LT has everything we expect in a competent softshell making it very versatile. It provides excellent moisture resistance, it has super breathable and durable fabric, gusseted underarms, stretch wrist gussets, a helmet-compatible two-way adjustable hood, two harness-compatible zippered hand pockets, and one internal zippered pocket. It also has an adjustable drawcord hem, a drop back hem for better coverage, and an athletic-fit for a slim, flattering profile. While the cuffs aren't adjustable, they are a decent size, and the stretch gusset allows them to stay put when pushed up to the forearms.

This shell easily fit a helmet under the hood and the pockets remain accessible with a harness or backpack on.
Photo: Penney Garrett
Value
This is a decently expensive jacket, no surprise. However, we think it's priced fairly for how well-made and high performing it is. The material is exceptionally durable, so there's little doubt it will last a long time and pay for itself over and over again. It handles like a champ on alpine climbs and cooler-weather multi-pitches and is even great on warmer ice climbing days. That said, if you're primarily going to be in severe weather, this layer alone won't be enough — you will want a hardshell to protect from the rain &/or an insulating layer underneath. However, if your adventure time will also be spent in warmer temps or engaging in highly aerobic activities, this is an excellent and versatile layer to have in your gear closet.

We loved having the Gamma LT around for milder climbing days. It moved and breathed with us like a pro and was durable enough to handle all manner of scraping and scuffing against the rock.
Photo: Penney Garrett
Conclusion
In many ways, the Arc'teryx Gamma LT Hoody is a favorite in our review. It is a damn fine jacket that breathes impeccably, moves with ease, and can withstand getting scratched and scuffed with no problem. It has all the right features for a plethora of outdoor adventures. While it's not thick or insulative enough for super intense wind or cold, its slim cut can easily fit under another burlier layer or over an insulating layer. Bottom line, we love this jacket and think it's an excellent layer at a committing-but-not-crazy price point that will serve you well for many years and many outings.

While a bit technical looking, we love the fit and feel of this jacket and found ourselves grabbing it for anything from a day in the mountains to drinks with friends.
Photo: Penney Garrett