Arc'teryx Alpha SL Jacket Review

A waterproof and windproof hardshell is the heart of my outdoor adventure kit. It is a piece of gear that goes on every single trip from a short day hike on my favorite local mountain to week-long backpacks in remote areas. Over the last year I searched for a new favorite hardshell, and I think I finally found it in the Arc’teryx Alpha SL.

Alpha SL Jacket on Wonderland Trail day hike. Picture by Grace Giordano. Alpha SL Jacket on a Wonderland Trail day hike. Picture by Grace Giordano. Review by Claire Giordano.

At the end of September I took the jacket a slew of day hikes and a multi-day backpacking trip. Fall hiking in Washington guarantees a mixed bag of weather, and we got a little bit of everything from rain to cold wind and sunshine. I was happy through it all in the Alpha SL.

The first thing I noticed about the jacket is how LIGHT it is. The women’s jacket (size M) clocked in at a pleasant 9.3 oz. This shaves significant ounces off the other jackets I usually carry, and I barely noticed the jacket while wearing it. The GORE-TEX® PacLite® fabric is not only light, but is less crinkly and compresses into a stuff sack that came with the jacket. Lightweight and packable, it was a no brainer to take it with me everyday.

Jacket Fit

Arc’teryx advertises this jacket as “trim fit.” For me this means it not only looks good with just a base layer on underneath but also has room for a light fleece and a mid-weight down layer. As an active outdoorswoman I like the fit of Arc’teryx clothing in my shoulders and this does not disappoint. I also appreciate the shell’s mobility thanks to the “articulated patterning” and “no-lift gusseted underarms.” What these fancy terms mean is I can scramble around steep trails, climb over big boulders, and lift things all without any uncomfortable pulling or restriction of movement.


Over the course of the trip I spent about a quarter of every day in this jacket. Each morning and evening the jacket went on over my other layers to add warmth and rain protection while making dinner and exploring in camp. Again, this is where the careful fit shines, as I had full mobility of my arms even with lots of layers.

The real test of the jacket, however, is how it did while moving. I wore it mostly because of wind, since we hit everything from gentle breeze to huddle-behind-a-rock-to-eat wind, which meant I spent a lot of time on the move in the jacket (I want to do a rainy humid day test soon). In these conditions I wore a wool t-shirt and Phase AR base layer beneath the jacket and was pleasantly surprised to not overheat (unless the wind died down). From decent uphills to flat off trail rambling, I easily regulated my temperature with the main zipper. After a few hours there was almost no moisture in the jacket. I also realized that while the jacket lacks underarm zippers (more on that below), this has the added benefit of more breathability through the fabric (zippers are huge swaths of non-breathable fabric right under your arm).

The sun came out but the jacket stayed on. The sun came out but the jacket stayed on.

For some hikers and climbers the lack of underarm zippers is a dealbreaker, as they want the extra ventilation. For me personally, however, I rarely use the zips on my jackets that have them (even while hiking in heavy rain) and did not miss them on this trip. There are a few reasons for this. First, with a backpack on the pit zips in my other coats often don’t open all the way or just end up folded over anyway, so do not add much extra ventilation for the weight and cost. Second, I am willing to sacrifice the zippers for the lightness of the jacket. Ultimately, it is up to you to decide what features are important to you.


The Alpha SL is now my go-to hardshell for all my upcoming trips. It is lightweight, comfortable, and packable, so there is no excuse not to throw it in my pack (or even my purse!) for when the weather turns whether I am backpacking or around town. This jacket also comes in at a decent price point ($279) compared to other jackets from Arc'teryx.

Come check it out next time you are in Seattle!

*Please note that we have a limited selection of sizes because we are small outdoor shop. Currently, we only carry this specific jacket for women (but have a number of similar products for men).