At 13 Ounces, Active Midlayer Offers Surprising Warmth: Arc’teryx Atom Hoody Review

A handful of items live in my backcountry ski pack all season, regardless of where I’m going or how long I ski. The list includes a waterproof and windproof shell, Voile ski straps, an avi shovel and probe, a pair of glacier goggles, a bar of skin wax, a hand tool, and, as of last spring, I added the Arc’teryx Atom Hoody as an emergency layer.

This lightweight insulated jacket is perfect for active outdoor pursuits such as backcountry skiing. This fall, I also used it for hiking, traveling, and wearing around town. And, with a waterproof shell over it, there wasn’t much weather I encountered in Colorado that required a beefier midlayer.

In 2025, Arc’teryx updated the Atom with FC0-DWR (fluorocarbon-free durable water repellent) finish. I tested the new Atom to see how the upgraded jacket would fare in Colorado’s spring and fall weather. Now, heading into winter, I’m more than confident that it will continue to keep me warm in even colder conditions.

In short: The Arc’teryx Atom Hoody ($300) is a technical midlayer for midlevel output activities. It’s thermo-mapped with Coreloft synthetic insulation and has full-length stretch fleece side panels for greater breathability and ease of movement. The lining is made of recycled nylon ripstop, and the face fabric is treated with PFAS-free FC0-DWR for light water resistance. For active pursuits in cold weather, this is a great option.

Compare the Arc’teryx Atom Hoody to others we’ve tested by consulting GearJunkie’s guide to the Best Synthetic Insulated Jackets.

Arc’teryx Atom Hoody Review

Arc’teryx designed this jacket for mid-output outdoor pursuits. It can easily transition to be worn out casually around town, but it was designed for alpine adventures and active use.

There’s a reason this jacket is ranked as GearJunkie’s Best Overall Insulated Jacket in our guide to the Best Synthetic Insulated Jackets. It’s easy to move in, breathable, the insulation is strategically mapped, and it’s light and pretty packable.

For most of my late spring and fall adventures, it was almost too warm when I was doing anything high-output — skinning or hiking up steep slopes, or going for brisk jogs in the early morning, for example. However, for mid- and lower-output activities, it was perfect. And if the sky ever opened up and temperatures really dropped, I would have been very grateful to have this jacket in my pack.

Fit & Layout

The Atom Hoody is fitted and has a trim look. However, it’s not restrictive, allowing for easy movement. You can still wear a layer underneath it if it’s really frigid out, and it still fits well under a shell.

Other GearJunkie testers found that the Atom fits a bit on the small side (although I didn’t experience that problem). Since it’s a fitted garment, I’d recommend trying the jacket on before making your purchase.

Arc’teryx used a minimalist design for the Atom. There are only three pockets (two hip pockets on the outside, and one inner chest pocket). There is an elastic cinch cord around the hem, and the hood is helmet compatible with its own cinch. The cuffs have an elastic closure that’s comfortable on the wrists and tucks easily into a glove.

Materials

The face fabric of the Atom is wind-resistant Tyono ripstop that is snag-resistant, abrasion-resistant, and doesn’t pill, according to Arc’teryx. It feels light and soft to the touch and is treated with PFAS-free FC0-DWR for light water resistance. Note, though, that this jacket is not waterproof. While the synthetic insulation will maintain your body heat if it gets wet, the Atom won’t actively repel water.

Recycled Coreloft synthetic insulation traps heat close to the body well. It’s been strategically placed throughout this layer to help prevent overheating. The side panels are also strategically made with stretchy fleece to enhance range and freedom of movement, as well as breathability.

The jacket’s soft ripstop face material is also recycled.

Weight & Packability

Of the jackets we tested for our guide to the Best Synthetic Insulated Jackets, the Arc’teryx Atom Insulated Hoody falls in the middle in terms of weight. At just 12.5 ounces, it’s not the lightest on the list, but it’s still a competitive option.

I barely noticed the weight of this jacket in my ski or hiking packs, or when I was wearing it. For any cold outdoor pursuit where weight is an issue, this is a solid option.

The Atom packs down well and easily fits into a pack. It isn’t as compressible as some traditional down jackets, or even other lightweight synthetic ones. As other testers noted, it does not come with its own stuff sack. But it won’t hog up too much space when you stuff it into a pack.

Arc’teryx Atom Insulated Hoody: In the Field

I wore this jacket throughout the spring on hikes around Glenwood Springs and Leadville, Colo. I wore it out on cold fall morning dog walks, and when I was camping, making coffee in brisk early morning air.

Admittedly, I did not get to test this jacket in the dead of winter, and I look forward to seeing how it performs in much colder weather than I have exposed it to so far. I’ll update this review with any further impressions from that testing.

The most notable factor about this jacket, in my opinion, is its breathability. When I was hiking and working up a sweat, I never felt clammy; I could still soak through my baselayer. But the Tyono ripstop face material, synthetic insulation, and ripstop lining worked well together to respire and manage moisture.

Warmth-wise, I was never disappointed in this jacket. In fact, it was too much for many of the days that I took it out with me. This is a very warm piece. Under a shell, I wouldn’t hesitate to venture out into the coldest weather I encounter in Colorado. For those bitterly cold days, you’d be just fine with the Atom and a baselayer under your shell.

Packability and weight-wise, I never had issues stuffing the Atom into full packs. The weight is negligible, and while it’s not the most packable jacket out there, I could almost always make it fit where I needed it to.

It’s also a great travel garment. It’s just as at home outdoors as it is in town, at an airport, or on a train. For ski trips, climbing trips, hiking trips, or any other adventure where you need a jacket that can transition seamlessly from trail to town, the Atom is a top pick.

Who Is It For?

Skiers, climbers, hikers, and alpine adventurers will love the Atom Insulated Hoody. It’s a versatile piece that packs a lot of heat into a lightweight package. It breathes well and offers a great range of movement, making it a prime layer for active pursuits in cold environments.

It might be overkill if you just need a puffy jacket for walking your dog, or going out to dinner — but if you also use it for outdoor activities, it has double the value because it swings both ways.

I’m excited to test this jacket in colder weather this winter, in environments and conditions that are probably better suited for it. So far, it has been an awesome insulated companion for hiking and wearing around in spring and fall. This winter, it will hold its place in my backcountry ski pack with all the other gear that never leaves it.