Arc'teryxMen's Atom LT Jacket

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The Details

The Men's Atom LT Jacket from Arc'teryx is a lightweight, synthetic insulated mid layer. The cold temperatures of Alert, the northernmost permanently inhabited location in the world won't keep you inside when you layer up with the Men's Atom LT Jacket. This lightweight and compressible, jacket features Coreloft insulation in the torso and arms. The side panels and underarms feature Polartec Power Stretch with Hardface Technology, delivering stretch mobility and breathability. A wind and moisture resistant outer shell makes it possible to use the Men's Atom LT Jacket on its own.

ATOM SERIES - Synthetic insulated mid layers | LT: Lightweight. Insulated, mid-layer jacket with wind and moisture resistant outer face fabric; Ideal as a layering piece for cold weather activities.

DESCRIPTION - This trim hybrid jacket is designed as an active-use insulation layer, providing vital core warmth with liberal mobility and breathability. Lightweight and compressible, the Atom LT Jacket features Coreloft insulation in the torso and arms. The side panels and underarms feature Polartec Power Stretch with Hardface Technology, delivering stretch mobility and breathability. A wind and moisture resistant outer shell extends stand-alone usability.

ESSENTIAL PIECE - Fact: Every person at Head Office owns at least one Atom LT; most of the women have two. The reason: Coreloft insulation inside a light taffeta shell. All the comfort of a sleeping bag, but it feels weightless.

WINDSHELL - The benefit of taffeta fabrics is their light, airy nature with an ability to turn aside wind. The Atom series have a taffeta outer lining that is treated with DWR (durable water resistant) finish to give them a long-lasting ability to shed moisture. In light precipitation, the Atom LT can be worn as an outer layer.

NO SWEAT - Mid layers that can function as outer layers have varied degrees of weather shedding capability; they also have varied degrees of moisture management. In addition to being made of breathable Coreloft insulation, the Atom LT has breathable side panels of Polartec Power Stretch with Hardface technology to help regulate temperature during exertion.

PACK LIGHT - Highly compressible, Atom pieces pack down into a tiny parcel of stored warmth. Store the jacket inside its own pocket, or tuck it into a sleeve or inside the hood if you are not restricted by space. A quick shake restores the original loft, time and again.

ARC'TERYX CORELOFT INSULATION - Developed by Arc'teryx, Coreloft is a synthetic insulation made of staple fibres in mixed sizes that are crimped to trap air and retain warmth. Available in different thicknesses for end-use performance and comfort.
Lightweight and highly compressible
Durable and resilient
Retains its warmth in humid and wet conditions and dries quickly if wet

ARC'TERYX FIT GUIDE - TRIM FIT - These trim fitting garments share motion-friendly traits with our Athletic fit, but are patterned with lower volume for reduced bulk. Our trim fit is sized for a base layer and a trim synthetic or down filled mid-layer

The Features

  • Features
  • Moisture-resistant outer face fabric
  • Breathable
  • Insulated
  • Lightweight
  • Compressible and packable
  • Wind resistant
  • DWR finish (Durable Water Repellent) helps bead water from fabric surface
  • Composite materials
  • Breathable, stretch side panels for enhanced comfort and mobility
  • Articulated elbows
  • Gusseted underarms
  • Soft brushed-lined collar
  • Full front zip with wind flap
  • Stretch-knit cuffs
  • Drop back hem
  • Laminated hem
  • Internal chest pocket
  • Two hand pockets
  • Fabric
  • •Polartec® Power Stretch® with Hardface® Technology—88% poylester, 12% spandex, 230 g/m². A four-way stretch fabric that allows for excellent athletic movement and good breathability to maintain comfort. Some products feature Hardface® Technology for a higher level of abrasion resistance.
    •Luminara™—Stretch nylon ripstop fabric with wind and water resistant, air permeable PU coating and DWR finish. A super lightweight and breathable stretch fabric with great water repellency and wind resistance.
    •60 g/m² Coreloft™ insulation
  • Fit
  • Athletic fit, Hip Length

10 Customer Reviews

Overall Rating

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We would like to hear from you. How would you rate & review the Atom LT Jacket?

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Cory Akin

When I first received this jacket, I was a little disappointed by the lack of , well, jacket. It's a very thin jacket. For it's price you would expect something like the Patagonia Down Sweater, which has substantially more girth.
But, after putting it to use, I am absolutely pleased with my purchase. For being a thin, slim fitting jacket, it is VERY warm. I use it as my insulating piece beneath an Arcteryx Theta SV, and the combination is perfect. It does a great job on colder days when temps are below freezing, although if the sun is out, and temps begin to climb at or slightly above freezing, I found the combination Atom LT/Theta SV was almost too warm. That's a good thing, in my opinion, being as I am confident I won't need any extra layers unless the temp REALLY drops.
For sizing purposes, I am 5'11", weight 180, have a 33-34 in waist, and I went with a Medium. The medium is perfect as a slim fitting, layering piece, although if I were to use this as an around-town jacket, I would go with a large for a more casual look. For reference, I wear a medium in the Patagonia Down Sweater, which is a nice, casual fit. So the Atom LT does fit slimmer.
In conclusion- great jacket, great for layering, very pleased

Humboldt Squid

This jacket receives my praise on so many accounts that even at full price, it feels like a bargain.
To better understand my use of the jacket, it may be worth noting that I live in a coastal desert region. My need for a jacket is limited to cold nights and mornings, a few short winter months, and travel to colder regions. That being said, the Atom LT is light, compressible and breathable, which warrants having it on me much longer than I would a heavier jacket. This is one of the main reasons for my purchase.
Others have mentioned that the piece does not appear very "technical" while still offering great performance. This jacket suits a casual setting just fine. Not everyone will care about that, but kudos to the bird for designing a jacket that excels in both performance and aesthetics.
Lastly, I am probably one of Arc's huskier customers, and I don't always get along with clothing labeled "athletic fit." The XL fits me JUST right and with excellent range of motion. It is like wearing nothing, and I don't look like the Stay Puft Marshmallow Man, which is a good thing..
Money well spent.


I've owned this jacket just over a year. I wear it everyday from October -March. It is the perfect piece for cold commuting on a bicycle and chilly days to the craig.
I was very skeptical of the Coreloft insulation before I had purchased the jacket, and now I am a believer. It regulates with your body temperature very well. Not quite as good as premium down, but it still works amazingly.
Thinking back on it, I wish I would have gotten the hooded version, but this piece is very nice, but it also passes for looking like casual jacket.
Don't get me wrong, I'm a huge gear whore, but I don't feel the need to have every jacket look like I'm geared up to Summit K2 when I'm going out to dinner.
For sizing, I'm a pretty thin guy. 6'0, 135lbs with an even ape index. And I think it fits very nicely. It's hard to find a medium that actually fits these days.
The only thing I would add would be elastic waist tensioner so the bottom was more form fitting to my actual waist.


Read the reviews. This jacket is awesome. I am not going to give you all the details. You will find them in the glowing reviews listed here and on other websites. I am up to my eyeballs in Arcteryx & Mammut jackets because they are the best overall quality. The Arcteryx Atom lt. is my all time favorite jacket. It is incredibly warm and light and looks outstanding. I have worn this jacket all winter by itself and as layer underneath a gore-shell jacket. It is a very versatile jacket for the spring, fall, and winter seasons. I am an athletic 5'9" at 160lbs and a large fits nice with room for a layer underneath. At the risk of sounding obsessed, I bought the hoody and vest version as well. I love this jacket. It is extremely versatile, light, warm, somewhat breathable, wind & water resistant. PS I bought the vest in medium for snugger fit.

Scott Jasper

I bought this jacket in 2009 and it remains one of my favorites. It feels great over a wide range of temperatures, say, down to the 20's (if you're active) and up into the 60's. It's light (my medium weighs 12.3 oz) and the trim fit looks great around town AND on the trail. The "Powerstretch panels" do a nice job with ventilation during exertion. Jacket does have an internal chest pocket which is not listed in Product Description above. There's no cinch at the waist hem, but it's stretchy and wind-up-my-back hasn't been a problem. I'm a big fan of the "stretch-knit cuffs" - Arc'teryx chose a sweet fabric and nifty design for this part of the jacket (and the cuffs just feel great on my wrists). I can't recommend this jacket enough.
Pic below shows Atom LT in spitting snow at 11,000 ft in the Wind River Range.

Light, but super warm jacket that can serve as as liner or stand alone as its own Jacket.

Wore this jacket in 40 degree temperatures with nothing but a t shirt underneath and was totally fine. Its creates a warmth that just simply does the job even in that cold/wet/nasty weather. Rain beads and rolls right off. Fit is snug, but comfortable in wrists and waist to retain warmth. I work outside on my feet where the temperature can be in the high 80's during the day and drop to 20 degrees when the wind changes direction. This is a great piece of gear to have on hand. This jacket is easily foldable into the small pouch of a camelbak or cargo pocket. It can be pulled out of nowhere to save you butt from the elements. Theres a reason Navy Seals use arc'teryx clothing. True story.


I've ordered, and returned, two of these jackets so far.
The good: They are fantastic in build quality and fit, and in short trials walking the dog (tags still on) they are very warm. I'm looking forward to getting my third one.
The bad: the color pictures on the website (and on Arc'teryx's website) are not accurate indications of the color of the jacket. For example: Squid Ink, which looks to be a nice blue/periwinkle, is actually a deep purple; Tibetan Red, which looks like a nice dark red, is also more purple than red, with a ridiculous light orange lining.
Not being man enough to pull either of those colors off, I'll be placing my my next order for the black version. Hopefully the third time will be the charm.

Great Insulated Layer

I bought this for my husband two years ago when he told me his inner layer for his Columbia jacket was worn out. He really like how snugged it fit him and he was even able to wear this layer in addition to his 3-in-1 Columbia jacket. He doesn't like the bulky look and said this layer was very light and kept him warm. I do find this brand Arcteryx to be a bit pricey but it does live up to all the hype (it is actually on sale now, I paid $250 for it). We live in the East Coast so it gets very cold here and my husband likes that he can layer up without all the weight.

Best Synthetic Insulation Out There

I have owned this jacket for over a year and have gotten more use out of it than I ever thought I would. It is super light weight, feels like you aren't even wearing it, and it packs down really small. This jacket goes with me on every backpacking trip in case the temps drop. It is super warm, you can wear it down to about 20 degrees, and it sheds water pretty well. I also like that it doesn't have the baffled construction so you can wear it around town without getting too many looks. Overall this lives up to traditional Arcteryx standards, they just get all the little things right and this is no exception.

Amazing jacket !

Got my Atom today and wow! Was wondering mostly about sizing -- at 5'10" / 165 lbs, I was planning to buy the small to go under my size small Beta AR. So after an online question/answer session with 'Snuggy' at, I ordered the medium and am glad I did -- fits perfectly under my size small Beta AR. Did I mention how toasty and light this thing is? This coat packs a big punch of warm for being so svelte. You will not regret getting this jacket! The perfect mid-layer or spring/fall jacket.I live in Michigan and wanted a jacket for three seasons ... this is the one. Look no further!