Arcteryx Atom SL – Insulated Jacket

I was lucky enough to be given an Atom SL jacket by Arcteryx this year in mid March and I’ve been putting it through its paces whilst living my weekend warrior life style out here on the West coast. I feel like it’s had enough varied and fun days out to now give it a solid review.

Arcteryx atom SL

The Atom SL is the newest and lightest edition to Arcteryx’s Atom family which are a series of alpine oriented jackets providing light synthetic insulation for all seasons. The Atom AR (All Round) is the heaviest (415g) and warmest of the series and the Atom LT (Light) was the lightest version (330g) but now the SL (Super Light) takes over that position (235g) moving the LT into mid table.


I first saw the SL on display as a prize at this years VIMFF and at first I didn’t bother to enter because I thought it was a Squamish Hoody and I already have (and love!) one of those. At first glance the SL really does look as light weight as Arcteryx’s very popular and very thin windproof, but on closer inspection it is much more than that.

It has to be said before I get into how much more it is, that I wasn’t overly convinced by the SL at this point. I utterly love my Squamish Hoody, it’s the perfect amount of protection for me to go from just under a comfortable temperature to just over in such a thin and light weight (140g) layer AND it packs down so efficiently into its own pocket that I couldn’t see anything rivaling it as a multi-pitch climbing piece or on alpine rock where I would want to hang the jacket from my harness.

The SL has the potential to go about half the size shown here (somewhere between the Squamish Hoody and the Nuclei) but it’s pocket is large and it expands to fit the bag it is in.

Yes, for sure there would be times when I would be colder and I would want more insulation; at belay stations in colder temps or on overnight bivi’s, but by that point, I would be personally looking at something like Arcteryx’s Nuclei jacket, (which is another astonishingly light alpine jacket but is much warmer than the SL) or a much heavier insulation piece like a bigger down or other synthetic. The point is that whilst the SL stacked up great in the specs and was very well made as expected with Arcteryx’s high standards, I just wasn’t sure I could justify it had a niche in my gear closet as a rock climber and Alpine rock enthusiast.

The SL features a face fabric made of 20 denier Tyono which is Arcteryx’s light weight and durable nylon and they placed their trademark synthetic insulation Coreloft at 40g/m2 in the essential areas around the core (chest and back). The Coreloft has apparently been specially treated to reduce its thickness by 50% but retain its thermal properties. You can really see the thinness of the insulation as the jacket almost looks translucent.

Atom SL coreloft

A very thin 40mg/m2 of Coreloft in the jacket’s core location.

They also added a strip of ‘Torrent’, their elasticated polyester at the under arms running all the way down the sides of your abdomen making the jacket super flexible and breathable and helps to make it a snug fit. The elasticated strip makes it really handy to pull up the sleeves if your getting warmer as I often did climbing or you want your hands to be free for jamming. When the arms are pulled down Arcteryx added an awesome little detail where the Nylon curves down the back of your hand to stop the wind shooting up your sleeve and make you feel less exposed which I really like.

Cuffs and flanks

Cuff detail and elasticated polyester flanks.

As soon as I picked it up on a fair but mild March day I put the jacket on to ride my bike home from the Arcteryx shop on West 4th in Vancouver. I got a medium and I’m 5’7ft tall and weigh about 135pounds. It fits perfectly. It is slim fitting as it’s a light weight jacket and is intended for layering, but I’m typically a medium in most Arcteryx Jackets so wouldn’t say it fits small particularly.


The fit from the back

The fit from the side

The fit from the side

I was immediately surprised at how warm and snug it felt for such a light jacket. I have noticed that there is just something about all Arcteryx jackets that just feels good against your skin. Maybe it is that they fit me particularly well or maybe there is some science to it that makes them fit everybody well like that, but the Atom SL certainly lived up to this. The jacket has a light weight mesh in the arms where there isn’t insulation to stop the nylon from touching your skin directly and feeling sticky, maybe this is part of it too.

atom sl arms mesh lining

Mesh lining at the arms feels soft and stops the Nylon sticking to your skin.

The hood is also very well fitting and sits over a helmet easily but the draw cord allows you to easily sinch it so it fits without a helmet.

Atom SL

Sinching the hood

As I was riding my bike I could immediately feel the jacket resisting the wind as I pinned it down West 4th and as I hoofed it up hill to my home I was definitely getting sweaty but the jacket was certainly breathing whilst I was working. I started wearing it a lot on my daily commute actually and it performed really well even in light rain and colder temps.However bike commuting is not why I would buy this super light jacket designed for athletes so as soon as the weather in Squamish gave even an ounce of hope of climbing my friend Paulie and I hit up the Apron to see what was dry. It was a pretty cloudy and cold day and we managed to find some wet and desperate slabs to climb. The jacket was almost perfect for this type of day as I would have been pretty freezing in these temps at the belay station in just my Squamish Hoody and it was even cold enough for me to keep it on during some pitches too. It fits well under the harness and I didn’t find that it was riding up (as so many jackets do) when I reached above my head. The jacket stretched well with my body and felt durable enough to be ok with it occasionally scraping against rock.

Multi-pitching in Squamish in less than ideal conditions.

Multi-pitching in Squamish in less than ideal conditions.

One thing that really disappoints me about this jacket is that it does not allow you to easily fold it into its own pocket. This to me is utterly essential for any jacket to be considered for use when multi-pitch climbing. It doesn’t even come with its own stuff sack which is not nearly as good as going in the pocket but the next best thing. Don’t get me wrong it packs pretty small – I put it in a stuff sack I owned and it was just a little bigger than the Squamish Hoody packed down. The first problem is that it doesn’t have a double zip so that makes life hard when trying to stuff it and un-stuff it. Secondly it also has a massive front pocket which means the jacket sits uncompressed in a large and long shape that is much bigger than its potential – it can pack to almost half the size of what you see in the photos. Lastly, the jacket doesn’t have a dedicated Caribiner loop – for me this is another essential feature if the jacket is to be used for climbing. In fact I jerry-rigged my own with some 2mm cord tied to the zipper for other multi pitch climbs we did.

Packed into it's own pocket with a cord tied round the zipper.

Packed into it’s own pocket with a cord tied round the zipper.

As well as multi-pitch climbing, cragging and biking I was lucky enough to be able to take this jacket on a 3 day ski trip when I did the Garibaldi Neve traverse over Easter (see blog here). The jacket really came into its own here as due to its lightness and compressibility it was an easy choice for my pack and was an ideal weight to throw on at pitt stops  where I would have got cold at such elevations with just a windproof, but I didn’t want to lug around a heavier jacket as I already had a super warm down for the overnighter.


Stopping to check out the way on the Garibaldi Neve traverse.

I think this is where the jacket really came into its own. Whilst it can be worn for climbing and I will continue to do just that, I now think that where Arcterxy were  really going with this jacket is as a layering piece when moving in the mountains in cold temps; ski-touring in the back country, hitting some piste runs on a colder day when you need that extra insulation but also high breathability, perhaps hiking on a summers day but needing a light layer for when the sun goes down or for wearing during those shoulder season hikes. I think this will work great for those people that particularly run cold and need just a little extra in a cold mountain environment but for me insulation is usually for being sedentary, those ski transitions or belaying, not for when I’m on the move (unless its really really cold!).

climbing Atom SL

Doing some fun things in my Atom SL

So in summary, while the shoulder season continues to prevail i’ll happily continue bike commuting and cragging in it since the Atom SL is a great jacket in so many ways and the high level of Arcteryx craftmanship is clearly visible. However unless Arcteryx start to put a more efficient packing system into this jacket for climbing and hanging it on your harness I don’t think I could justify it as a piece among my already expansive gear closet. I can see how the jacket would be a fantastic layering piece and now I have it I’ll be happy for it to sneak its way into my backpack on many alpine and overnight trips, but I’m not convinced it would have typically worked with how I normally system my layering. Nonetheless, if you are looking for a really light weight and highly insulative jacket that would work well as a layering piece, I would not be overlooking this jacket!



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