#Note: Full Arc'teryx review list is at the bottom.
For Spring/Summer 2021, Arc'teryx just released a new piece to their Atom line: Atom SL Anorak.
But for the US, the Atom SL Anorak is only available just yet (mid February).
This delay actually isn't exclusive to 2021, and instead, Arc'teryx always seems to be late to release Spring/Summer updates to the US for some reason.
Atom SL Anorak is designed for milder temperatures (chilly spring & summer mornings) where mid to high output activity is expected. It's quite a bit windproof, but offers below average waterproofing.
Due to the lack of insulation in the arms (mesh lined sleeves) as well as the minimal amount of insulation in the body, Atom SL Anorak will have breathability in mind when high output activity is the goal.
Among the entire Arc'teryx insulated jacket army, Atom SL and Atom SL Anorak are the ones that offer the least amount of warmth. They offer the lightest density of insulation (Coreloft 40 (40 g/m²)). Arms are NOT insulated.
As you can see, Atom SL is down at the bottom in this table (temperature rating of Atom SL Anorak is identical with that of Atom SL):
But, since this anorak is designed for high output activities in chilly summer mornings, this isn't (shouldn't be) the main thing to expect from this piece. It isn't, after all, what it's trying to accomplish.
What Atom SL is trying to accomplish is a top-notch breathability, and it does a perfect job with that.
This is (should be) the main buying point for not only the Atom SL Anorak but also the Atom SL. Tyono 20 outer fabric and fleece side panels of Atom SL Anorak do a pretty good job together to keep you ventilated.
The only reasonable alternative you would have to Atom SL Anorak would be the Proton FL. Proton FL also provides perfect breathability. It's actually even slightly more breathable.
Read my Proton FL vs Atom SL comparison for more information about both.
Tyono 20 of Atom SL is quite a bit wind proof. During spring & summer, wind proofing is a higher priority than water proofing when enjoying outdoors. It's especially necessary during any high output activity.
As I explained earlier into the post, Atom SL Anorak is also equipped with a chest pocket, unlike most other Arc'teryx insulated jackets - which are equipped with typical hand pockets.
When this pocket configuration is combined with its superior windproofing capability Atom SL Anorak becomes a pretty good option for climbing folks.
DWR is a coating.
It's basically sprayed on to the surface of these jackets as a finish. It stands for Durable Water Repellent - which means that water will be repelled under wet conditions instead of soaking into the fabric.
DWR also decreases dry time.
It's a good thing these jackets are coated in DWR, but pay attention to the fact that DWR is a coating - meaning that it will wear off over time.
Which is why you might want to invest in a DWR spray such as this one for after treatment.
As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%. I explained why this happens here in this post of mine.
Atom SL Anorak fits very trim. Front hem is also longer than that of Atom LT.
Atom SL vs Atom SL Anorak
- Atom SL Anorak comes with a 3/4 zip, and offers only one chest pocket; instead of two side pockets of Atom SL.
And which one would be better for you? Depends.
Unless Atom SL Anorak fits your body type (skinny build) and/or you'll be climbing with this piece 95% of the time...
...then I think I'd get the Atom SL over Atom SL Anorak any day.
Here's a good video review of Atom SL Anorak: