Arc’teryx Atom SL

Insulation is always a compromise when out running on the trail. Often we want to carry something in case the worse happens, but the bulk and weight penalty means that protective layer stays at basecamp. Even in the depths of summer, temperatures drop at night and that little extra can make the difference between a comfortable and regrettable experience.

What the brand say:

“Warm weather is never a constant, even in summer. Fog rolls in, a sudden thunderstorm blocks the sun, and changes in elevation and levels of exposure can cause temperatures to suddenly shift. But summer conditions seldom require bulky insulation. The Atom SL Hoody is specifically created to hit the zone where insulation is required, but in a measured amount that suits milder conditions. Providing warmth comparable to a lightweight fleece for significantly fewer grams, the Atom SL is an efficient midlayer in cool conditions and a great standalone during rest breaks, early morning starts, and while enjoying the view from a freshly bagged peak.”

Arc’teryx have taken this requirement head on, with their Atom SL or Super Light. Based on their legendary Atom LT and SV jackets, the SL is an ultra light, synthetic insulated jacket for those summer months when you need to travel light and fast, without a full-blown synthetic or down jacket.

Now, it’s March and I’ve had the SL since December, hardly the perfect testing conditions on paper. However, with the mild winter, I’ve been able to effectively live in the jacket, from day to day, pre/post runs and mountain biking. The fact it has become a daily piece of clothing is an indication of the Atom SL’s versatility.First off its light, with my size small weighing in at 249g. More than this, it feels light when worn and more akin to a wind shell than an insulating piece. With this light weight comes good compressibility, with the ability to stuff it into any nook and cranny you find free in your pack.

The construction of the jacket has four main sections. The torso, oblique’s, arms and hood.

The entire jacket has a lightweight Tyono™ 20 denier shell with DWR treatment which manages the balance that fine line between wind resistance and breathability well. If the weather picks up and the winds gets bitter, you will feel the chill, but for most conditions the shell does a great job of regulating temperature and sweat.

Torso – The main body is comprised of a lightweight shell which contains 40g/m² Coreloft™ Compact insulation to provide warmth. Coreloft™ is Arc’teryx’s own synthetic insulation which works in all conditions. The weight of insulation is important, too little and it is inadequate, too much and it becomes a layer designed for cold weather climates or sedentary activity. The 40g/m² keeps you warm, holding off chills, but allows you to move quickly without becoming saturated with sweat.Obliques – Combined with the Coreloft™ torso, the obliques have a stretch fleece side. Constructed from Torrent™, it is both moisture wicking, breathable and stretchy. The jersey knit textile has a soft, brushed surface and a Polygiene® finish to manage odour. Side walls allow for greater breathability and moisture management, along with helping those twisting core moves. The Polygiene® silver ion treatment does a great job holding off the build up of odours and the fleece inclusion keeps the jacket close to the body, preventing it from flapping in the wind.Sleeves – Rather than having pure shell on the skin, the sleeves are mesh lined, which reduces the likeliness of them sticking when things get hot, but also aids moisture wicking. The inner arm feeds from the obliqes with Torrent™ fleece, provided increased wicking and breathability. When the terrain gets vertical and you need to scramble the sleeves are articulated, with gusseted underarms to extend your freedom of movement. I never noticed the sleeves or thought they were a nuisance for riding up, so as far as I can see, the articulation works. The shaped cuffs fit well, close enough to protect, yet not so close that they are restrictive.

Hood – I can happily inform, instead of a simple hood with an elasticated hem, a once size fits all, the Atom SL has an adjustable hood, with wire peak and elastic cord which promotes a custom fit. If I have a hood on a jacket, I want it to be customizable to my needs at the time and I can report Arc’teryx have produced one of the best I have come across. Even though it may be only a shell, with no insulation, it makes a noticeable difference when up and cinched down. The StormHood™ is a thing of beauty, with Arc’teryx’s renowned refined design details.So the question on everyone’s lips is do these four elements work together as one. In short, yes. Despite having four distinguishable zones, they seamlessly work together.

The body contains a main front zip, with a No Slip Zip™ to prevent it from opening when not fully closed to the top. At the top of the zip there is a soft chin guard, which caused me and my stubbly face no irritation. Behind the zip there is a wind flap, which after many days of high winds, does its job well.

Either side of the main zipper, a zippered hand pocket is located. Long and reasonably wide, they comfortable take hands as advertised, along with a variety of similar sized objects.

An adjustable hem with toggle makes closing the bottom tight when the elements pick up quick and easy.At £170 it comes at a price, at the same price as the Atom LT jacket and £20 less than the Atom LT hoody, it does make decsions that bit trickier. The question is how light are you willing to go?

From the heights of the Lake District, to sitting around the house, the Atom SL has stuck to my body like glue. It’s versatility is paramount, the ultra light weight shell, stretch fleece and insulation combine to make a garment that is at home in all but the harshest conditions. It may be aimed at higher temperatures of summer, but I had no issues with using in the winter months and would happily continue to do so.