Last year I really started making a push to lighten my overall pack load and become what I considered to be a “lightweight backpacker”. As much as I have enjoyed that transition, it did come with some learning experiences. My first real “lightweight” mistake was last summer on Tour du Mont Blanc. I got swept up into the whole “summer weather is always nice” and “thunderstorms are usually warm” mindset before flying out to France. The first two days were great, as my lighter pack allowed me to coast up and down the steep mountain trails. It all changed on day three though, as a ‘once in a few decades’ storm hurdled towards the Alps. The final 70 miles of hiking through France, Italy, and Switzerland were in a cold and almost constant drizzle. I was lucky to have my rain gear, but I foolishly left behind my warm layers. Luckily, there are plenty of places to pick things up along the TMB, and I made sure to correct for my error as soon as we arrived to Courmayeur. After looking around in a few stores, I found my match made in heaven, the Arc’teryx Atom LT Hooded Insulated Jacket. I have now worn this jacket in all kinds of cold, rainy, and stormy conditions, and am excited to finally be writing a review.
Support Trail to Peak by purchasing this jacket on Amazon with the links below:
Atom LT Hoody | Atom LT No Hood

The Arc’teryx Atom LT Hooded Insulated Jacket is the perfect outer layer for all of your year-round mountain pursuits. I also love this jacket for a night out on the town (even though it usually smells like my work load would predict). For the outer shell of the Atom, Arc’teryx uses a DWR coated Tinthian material that is smooth, soft, and does a great job of resisting water and blocking wind. I’m able to wear this jacket in light rain and drizzle without having to put on my waterproof layer.
What I love most about the Atom is the way it breathes. I’ve always been the kind of guy who will deal with cold on hikes, because every jacket I’ve tried before this one would cause me to overheat and sweat through it. The Atom provides breathability with Polartec Power Stretch side panels.

Like most Arc’teryx gear, the Atom fits pefectly, and maintains a very athletic cut. I purchased the Atom in a size Medium. Both front pockets are zippered, and the jacket has a full zipper from waist to neck. The wrist sleeves on the Atom are elastic and felt a bit small at first, but I love how they clasp my wrist and keep any wind from getting in on gusty days. Just like the side panels, they also allow for breathability. It’s the perfect combination.

I buy all of my jackets with hoods, as I love being able to keep my head warm without having to carry a beanie. The StormHood on the Atom is helmet-compatible, although I have not worn this jacket climbing. I have taken it on some really nice hikes up to the summits of Mt. Whitney and Mt. Langley in really cold weather (20-30 degrees F). Having the hood on this jacket adds a ton of warmth, as no cold air sneaks in through my neck or head.

The Arc’teryx Atom LT Hooded Insulated Jacket keeps me warm with Coreloft insulation. If you’ve read my review on the Patagonia Down Sweater, you’ve heard me extol the virtues of real down when it comes to warmth. I love my Down Sweater in dry weather, around camp, and when I know I’m not going to be sweating. If there is a chance of wet weather, or a chance I’ll be going from sweaty to cold, I reach for the Coreloft synthetic down. Synthetic down is great because it keeps it’s warmth when wet, unlike real down. It also dries quicker. If you’re interested in reading more about types of insulation on jackets, I recommend this great post from Outdoor Gear Lab. As for this jacket, I have nothing but the highest praise for how it’s handled a multitude of cold and wet environments.
I give this jacket a solid 10/10 and it has my highest recommendation. It’s a little bit expensive at $250, but I’ve found it to be worth it’s weight in gold. This is my favorite cold weather jacket, and the piece I reach for more than any other.
Support Trail to Peak by purchasing this jacket on Amazon with the links below:
Atom LT Hoody | Atom LT No Hood

Great post. Thank you. My body went and got old. But I still like to hike and climb. Every ounce of lighter counts!
Thanks, Johanna! My body is starting to do the same 🙂
I use the Atom LT for rock and ice climbing and I agree – extremely well-designed, versatile, and worth the money. Excellent review!
Thanks, Jimmy!
Love the Atom LT as well! What pants are those?
These are the Outdoor Research Voodoo. I’ve worn these on the JMT and a few local hikes. I’ll have a review up once I get a chance to wear them in more cold/snowy conditions.
Great review and completely spot on. I have the jacket and hoody.
May I ask what kind of shoes are those?
Thanks Jaylar! I’m wearing the Nike Wildhorse 3 in that shot. They’ve been my favorite shoes this year. I’ve probably logged 400 miles on that pair in the High Sierra, Grand Canyon, and local mountains. They’re a great lightwieght hiker and trail shoe.
I hate hoods. They are bulky, get wet and your head can be so much more comfortable and well regulated in it’s own layer. Foolish is sweating under a hood or having the insulation layer for your head get soaked because it sticks out of your outer layer…
You’re right. What was he thinking offering his opinion? Maybe he should cut off the hood to comply with your standard.
Thanks for the helpful post.
Thanks, Chris!