REVIEW: Arc'teryx Atom LT Hoody

The Arc’teryx Atom LT Hoody Men’s & Women’s is one of those garments that you will find yourself making excuses to wear, even when it’s not quite appropriate. The good news is that this is a pretty darn versatile jacket, so excuses are often not required. Arc’teryx describes the Atom Lt as an active-use insulation layer, providing vital core warmth with liberal mobility and breathability. I’d be hard-pressed to give a more accurate description in 10 words or less, but there is also a lot more to this jacket than one might realise at first. It’s been a modern classic among outdoor enthusiasts for a while now & when an opportunity came to get into an Atom LT Hoody a couple of months ago, I was incredibly keen to sign up.

Design & Specs

Essentially the Atom LT Hoody is a synthetic based insulation piece that can serve as both a mid-layer or outer layer depending on the weather and your clothing system. This a lightweight jacket (approx 360g) so even light enough to consider taking when there is just a chance you’ll need it. The main body and arms of the jacket use synthetic insulation called Coreloft, which is essentially the proprietary Arc’teryx equivalent to the more widely known Primaloft. The rating or ‘weight’ of the Coreloft is 60 g/m² and it’s made from a highly crimped polyester yarn that both compresses well & retains its loft. The stretch side panels found down the side of the torso (under your arms) are Polartech Power Stretch with Hard-face technology, so warm highly stretchy fleece that also breathes very well. These panels serve to reduce the dreaded underarm bulk found in some warm jackets, plus they allow heat to vent when you’re working hard. The outer shell is a nylon taffeta fabric called Tyono, which super light and has a soft hand. But don’t let that fool you into thinking this is a weakling of a jacket, it’s also DWR treated and quite durable. The Atom LT is not a wind/waterproof jacket, but it’s quite wind and moisture resistant. Like most synthetic based insulated pieces, it’s perfect for both dry and moist conditions.

The fit is athletic, in the Arc’teryx sizing range, it’s a Trim Fit. So it’s close fitting but roomy enough for a base-layer and low-bulk mid-layer underneath. I found I could wear an Icebreaker 200gsm base layer, plus a 100 weight fleece under my large Atom LT, with a touch of room to spare (but I’m pretty skinny!). There is an elastic hem cinch and it’s slightly longer at the back to give you more ‘bum coverage’. The soft hand-warmer pockets sit high and don’t interfere with a climbing harness or pack hip belt. The sleeve cuffs are elasticated perfectly, snug enough to stop drafts but they expand so you can slide the sleeve us your forearm comfortably. The hood is simple but well considered. It’ll go over a helmet but can also cinch down using the elastic pull adjustment at the back for use without a helmet. There is no built-in stuff sack, but the jacket rolls easily into the hood and will stay quite compressed. Beyond that, the Atom LT is just simple and pared down, classic Arc’teryx: functional & comfortable.

A Study in Versatility

For me, adventure trips often involve a variety of activities and vast changes in weather. Finding clothing that will excel throughout the different needs and situations of this kind of journey is key, especially when keeping pack size and weight to a minimum is a priority. When choosing what to pack, I’ll look for gear that serves multiple duties but also isn’t a compromise. Sure, that’s a lot to ask, but modern clothing technology is pretty amazing and garments like the Atom LT can pack a lot of varied usability into one tidy package.

Coming from a QLD summer, I was very excited to get into the Atom LT upon arriving in Queenstown this last February. I’d even rolled the Atom into its hood and used it as a pillow on the plane, hoping to deploy it upon landing! The weather was sadly unseasonably warm when I arrived, but gladly it cooled considerably in the late evening. Thus began my love affair with the Atom LT. The next morning we were strolling along the lakeside together as the sun rose majestically above the mountains… Ok ok, I’ll keep it on track. In all seriousness I was impressed right from the start at the range of temperatures I could wear the Atom in, from cool windy evenings hovering around 15°C, to temps well below freezing later in the trip. The styling is understated, so I never felt out of place wearing the Atom around town, be it meeting a friend for dinner at a nice Queenstown restaurant, or stopping by the pub before (and after) forays into the mountains.

Early morning overlooking Lake Wakatipu, Queenstown.

Mountain Testing

The real test though was seeing how well it performed in harsh conditions. The New Zealand Southern Alps are renowned for wild and wet weather, any time of the year. Luckily for the first half of the trip, when I was doing some alpine climbing, the weather was fairly mild. I used the Atom a lot, around camp and even whilst sleeping in open bivouacs. The warm hood was great to sleep in when the temps below Mt. Brewster dipped below freezing overnight. Whilst climbing I was impressed by how well the Atom LT vented heat, but also kept me warm when stationary. Often I found myself just wearing the Atom over a long sleeve merino base-layer. There were only a few times when I felt the need to cover the Atom LT with my hard-shell jacket, such as the summit traverse on Mount Brewster and the subsequent wet, cold and prolonged rappels afterwards. Most of the time, the Atom alone whilst climbing was fine, it cut the wind and kept my body temperature well regulated.

L: Waiting in a crevasse whilst descending off Mount Brewster, the Atom Lt under my Theta AR Gore-Tex. R: Waking up at our bivvy below Mt. Brewster, there was ice on the bivvy sack so it was below freezing overnight.

Later in the trip, I walked through the Mount Aspiring National Park for a week, encountering 5 solid days of torrential rain, sleet, wind and snow. The temps never dropped too far below freezing, so I was able to get by wearing my base-layer, a light fleece and shell jacket whilst walking. The Atom LT was my saving grace, kept tucked away safely in a dry-sack in my rucksack. Always it was ready to bring my body temperature back into the happy place at the end of some hard, wet cold and long days. That said, knowing I could use it if required in the wet conditions was always an option, as the synthetic insulation would retain the vast majority of its thermal efficiency even when wet.

L: Venturing out once the rain began to ease, Dart Hut in the Background. R: Waiting out wet weather in Dart Hut

Initial Conclusions

If you haven’t guessed it already, I love this jacket. It served me very well in NZ and I’ve already had a chance to use it a couple more times here in QLD on some overnight climbing trips. My only gripe is that it’s too hot here in Brisbane to wear it most of the year, but that’s not really the Atom’s fault. If you’re looking for a light insulation piece that will fit into a huge range of adventures, definitely consider the Atom Lt. Hoody. Be warned, however, once you try it on you’ll want one. Trust me.