Proton/Atom vs Nano Air: First hand (temp ratings & more)

I've got the most recent (Winter 2024) models of all 3. 

These are the product pages of the most recent revisions: 

• https://arcteryx.com/us/en/shop/mens/proton-hoody
• https://arcteryx.com/us/en/shop/mens/atom-hoody
• https://arcteryx.com/us/en/shop/womens/proton-hoody
• https://arcteryx.com/us/en/shop/womens/atom-hoody 
• https://www.patagonia.com/product/mens-nano-air-insulated-hoody/84367.html
• https://www.patagonia.com/product/womens-nano-air-insulated-hoody/84268.html

Summary

My take is that these products are much more similar than they're different. The differences in things like warmth and breathability might not even be noticeable to you. 

Because of superior abrasion resistance capability of Proton (aka LT), I think that it's mostly the better pick for climbing and skiing in not-so-cold-but-still-chilly days. Also better resists against a heavy backpack. 

Atom (aka LT), on the other hand, is mostly the best choice for maximized breathability (side fleece panels). It also has the highest capability hood of all these (StormHood). 

Nano Air (the most recent 2024 version) is the best if you need packability, if you dislike elastic cuffs and/or if you have long arms. 

Like I said, however... These differences are small, man. That's why I don't see anything wrong in prioritizing the looks over anything else. 

Warmth

Warmth difference isn't really noticeable. 

Breathability

Atom (aka LT) literally destroys the Proton (aka LT) and Nano Air in this regard. 

I'd put the Proton and Nano Air at the same level of breathability. Proton can be slightly more breathable, but that's when we look at the tech specs. Definitely nothing noticeable going on in there. 

Wind resistance

Atom's side fleece panels is a double edged sword. It lets the wind in. When I'm cycling I'm especially aware of this. 

Not only because I'm going against the wind (i.e the wind's relative velocity is higher), but also because these mesh panels are more exposed since my arms are up. 

Proton and Nano Air again come very close in here. 

All are DWR coated. 

They do by the way have an additional hybrid models of both. That of Proton (aka LT) is Proton Hybrid Hoody, and of Nano Air is Nano Air Light Hybrid. I do own the former but not the latter. 

They're like a crossover between a synthetic insulated jacket and a softshell. 

This "upgrade" in face fabrics translate into better wind, water and abrasion resistance. But you give up insulation and breathability in return. 

Pockets

Amount of pockets is the same in all three. Find pocket dimensions below. 

• Nano Air: 
  • Hand warmers: 7.1 in (or 18 cm) x 11 in (or 28 cm)
  • External zippered chest pockets: 7.9 in (or 20 cm) x 9.9 in (or 25 cm)
• Atom:
  • Hand warmers: 10.6 in (or 27 cm) height x 7.1 in (or 18 cm) width
  • Internal zippered chest pocket: 9.9 in (or 25 cm) height x 7.5 in (or 19 cm) width
• Proton: 
  • Hand warmers: 9.4 in (or 24 cm) height x 7.5 in (or 19 cm) width

Packability

Nano Air is the only packable of all these three. 

It's packed into the external chest pocket. Packed size is 7.5 in (or 19 cm) x 7.5 in (or 19 cm) x 4 in (or 10 cm) but it's irregular in geometry, as you see. 

When I pack & unpack it ends up in a different shape so the dimensions (not the volume) can change slightly. 

Fit

I personally like Atom's and Proton's fit better and find them more comfortable. 

• Fit

Canberk is 5'11" and 165 pounds, with an athletic build. Size Medium fits him perfectly across almost all brands and product lines. 

• Arc'teryx's 2024 men's fit revision

Here's what Arc'teryx says about its most recent fit revision: 

Source: https://arcteryx.com/us/en/help/sizing/mens/tops/new

Not all jackets come with the revised fit - only the ones with following statement: