Active-use insulation is a tough balancing act.  Too breathable means too cold at rest, but too insulating means too hot during activity.  Arc’teryx strikes very close to the breathable / insulating bullseye with the Atom LT Hoody.

Arc’teryx Atom LT Hoody Features:

  • Front/back panels are 100% nylon Tyono 20 denier shell with DWR treatment
  • Side panels are 88% polyester, 12% elastane Polartec Power Stretch
  • 100% polyester Coreloft 60 g/m² insulation
  • Trim fit
  • Articulated elbows
  • Gusseted underarms
  • Insulated, helmet-compatible hood
  • Stretch-knit sleeve cuffs
  • Drop back hem
  • Internal chest zip pocket
  • Dual hand pockets with exterior lining
  • Weight: 360g / 12.7oz
  • MSRP $249
arcteryx atom lt hoody hiking

Spring hiking in the Atom LT Hoody.

Atom LT Delivers Active Insulation

Springtime is such a mixed bag: snowy and cold one week, warm and breezy the next.  In these conditions, versatile outerlayers are always appreciated – and for several weeks of early spring hiking and camping, the Arc’teryx Atom LT Hoody performed admirably in almost every situation.

A full description of this jacket is found in the name: the Atom series from Arc’teryx are midlayers made with hydrophobic synthetic insulation that resist absorbing moisture and retain warmth even when saturated. The LT (for lightweight) model is positioned between the minimalist SL and the more robust AR models, offering the most versatility between active use and insulation.  And the Hoody part is self-explanatory, although this jacket is available in a non-hooded version also.

arcteryx atom lt fabrics

Four Surfaces L to R: interior microfleece side panel, interior nylon, exterior nylon, exterior stretch mesh side panel

What distinguishes this midlayer from a lot of other midweight puffies on the market are the thin stretch panels on the side panels, which are very effective at ventilation under conditions of exertion.  These side panels have a very soft brushed microfleece on the interior surface, which contributes to the overall comfort of the jacket (more on that below). The tradeoff of insulation with the breathable side panels isn’t as much as you think, as the Atom LT kept us comfortable with temps into the 30s.  A trim torso fit allows this jacket to be layered under a shell for hardcore cold or moisture, and the four-way stretch properties of the side panels allow full range of motion when used as a standalone outer layer.

arcteryx atom lt interior pocket

Interior zip pocket on left chest.

The main panel fabric is a 20-denier nylon which proved durable when bouldering or bushwhacking, and the DWR finish held precipitation out for 20-30 minutes before the shell felt saturated.  The entire interior surface rides plush against the skin, and it’s easy to keep this jacket on for hours without even thinking about it.  On the back side, the drop-hem helps your waistline stay covered even when sitting or climbing around. Another comfort feature is the stretch cuffs, which are thin and light, but stay in place well and easily expand when putting the jacket on or off.  We only noticed one comfort drawback on windy days: if you’re not wearing the hood, the collar of the jacket extends quite a ways down the shoulders, and easily gets caught in gusts to flap against your cheek.

arcteryx atom lt stretch cuffs

The Atom LT features thin elastic stretch cuffs.

One construction quirk we found is the issue of stowability.  While the Atom LT is very easily compressible and can easily pack into either the chest pocket or hand pocket, none of the pockets on this jacket have a double-sided zipper mechanism for securing the packed garment.  Since we rarely zip our stowed pockets shut, this wasn’t a huge problem, but more of a weird design oversight.

arcteryx atom lt DWR

Active beading from DWR finish.

Like many Arc’teryx jackets, the Atom SL has a stylish look that is equally suitable for casual wear as well as active trail use. The textured cloth is also a nice departure from the commonplace puffy panel construction that you see virtually everywhere.

The Good

  • Great balance of breathability and insulation
  • Flexibly trim torso
  • Strong wind and water resistance

The Bad

  • High collar flaps too much if the hood is down

Bottom Line: Arc’teryx Atom LT Hoody

Ideal for light aerobic activities, cold-weather camping and hiking, or layering under a shell for harsh conditions, the Arc’teryx Atom LT is a highly versatile midlayer that stands apart from the puffy masses.

Buy Now: Available at REI

In Summary

7.2 Versatile Jacket

Arc'teryx doesn't mess around -- everything is of the utmost quality. With the Atom LT Hoody you get a mid layer that can breathe, but also withstands some decent weather as an outer layer. It's an admirable mix of both.

  • breathability 8
  • warmth 6
  • durability 7
  • protection 7
  • fit 8
  • value 7

About Author

Donald is a physical therapist, ultrarunner, barefoot aficionado, and father of three with more than 20 years of experience in endurance sports. When he's not training for ultramarathons, he enjoys hiking or slacklining with his family in Monterey County, CA.

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