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Arc’teryx Proton LT & Atom LT vs Patagonia Nano Air

Last updated: May 12, 2023 by

  • This article is revised after Arc'teryx FW23 update. 

Proton LT and Atom LT are revised for FW23.

New product pages (women's counterparts have been undergoing a naming scheme change, but it doesn't affect the product designs): 

Summary

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

So I'd base my decision primarily on my preference around the pocket configuration. Atom LT doesn't come with an external chest pocket, but an internal one. Proton LT and Nano Air both offer one chest pocket. 

Second, I'd take a look at the products and see which one looks more to my taste. 

Third, I'd compare the brands rather than the models. 

But if you STILL can't decide, then to maximize warmth and weather resistance, I'd pick Proton LT. To maximize breathability, I'd pick Atom LT. To maximize comfort, lightness and packability, pick I'd Nano Air. 

To find out more about these jackets, check out this chart: 

  • Data Set: Temperature Ratings of Synthetic Insulated Jackets

Approximate lowest temperatures you can wear each down jacket in the market without feeling uncomfortably cold are... 

NameEst. Temp (F/C)ReviewPit venting?Stuffs into itself?Two way zipper?TypeFill PowerFill Weight (grams)Fill Volume (FP x FW)Synthetic Insulator (SI)SI AmountFace FabricActivityFitWeightLength (CB)
Arc'teryx Alpha (Men's - Women's)-18/-28ReviewNoYesYesDown850296251,600Coreloft90 g/m²N30r 2L GoreTex InfiniumClimbingRegular805 g / 1 lb 12.4 oz86 cm / 34 in
Feathered Friends Khumbu-17/-27NoYesNoDown900378340,200Primaloft Gold200 gPretex Shield XTAll RoundRegular960 g / 2 lb 2 oz?
Arc'teryx Ceres SV (Men's - Women's)-15/-26ReviewNoYesYesDown850240204,000Coreloft?Arato 30All RoundRegular880 g / 1 lb 15 oz86 cm / 34 in
Mountain Equipment K7 (Men's)-13/-25NoYesYesDown800300240,000N/AN/A30D DriliteAll RoundRegular820 g / 1 lb 13 oz76 cm / 30 in
Rab Positron Pro (Men's)-13/-25NoYesYesDown800300240,000N/AN/A40D Pertex Quantum ProAll RoundRegular740 g / 1 lb 10 oz85 cm / 33.5 in
Arc'teryx Therme SV (Men's)-11/-24ReviewNoNoYesParka750211158,250Coreloft60 g/m²2L Gore-TexAround TownRegular1.072 kg / 2 lb 5.8 oz96 cm / 37.75 in
Patagonia Grade VII (Men's)-11/-24NoNoYesDown800335268,000N/AN/A1.2 oz 15 & 20D Perfex QuantumAround TownRegular743 g / 1 lb 10.1 oz83 cm / 32.5 in
Arc'teryx Firebee AR (Men's - Women's)-10/-23ReviewNoYesYesDown800225180,000N/AN/AArato 7 & 10All RoundRegular680 g / 1 lb 8 oz79 cm / 31 in
Mountain Equipment Exo (Men's)-10/-23NoYesYesDown800265212,000N/AN/ANylonAll RoundRegular770 g / 1 lb 11.2 oz79 cm / 31 in
Arc'teryx Thorsen (Men's)-7/-22ReviewNoNoYesParka750192144,000Coreloft60 g/m²90D 2L Gore-TexAround TownRegular1.1 kg / 2 lb 5.4 oz91 cm / 36 in
Patagonia Frozen Range (Men's - Women's)-6/-21ReviewNoNoNoParka700268187,600N/AN/A4 oz 75-denier polyesterAround TownRegular1.253 kg / 2 lb 12.2 oz84 cm / 33 in
Mountain Equipment Li. Ec. (Men's - Women's)-5/-20NoNoYesDown700295206,500N/AN/A50D DriliteAll RoundRegular822 g / 1 lb 13 oz72 cm / 28 in
Arc'teryx Patera Long (Women's)-2/-19NoNoYesParka7507455,500Coreloft60 + 80 g/m²2L Gore-TexAround TownRegular1.1 kg / 2 lb 6.8 oz117.5 cm / 46.25 in
Rab Neutrino Pro (Men's - Women's)-2/-19NoYesYesDown800212169,600N/AN/A20D Pertex Quantum ProAll RoundRegular585 g / 1 lb 8.6 oz77 cm / 30.3 in
Arc'teryx Dually Belay (Men's)0/-18ReviewNoYesYesSyntheticN/AN/AN/AThermaTek92 g/m²30D NylonAround TownRegular705 g / 1 lb 9 oz84 cm / 33 in
Arc'teryx Centrale (Women's)0/-18ReviewNoNoYesParka750157117,750Coreloft60 g/m²N90p NylonAround TownRegular885 g / 1 lb 15.2 oz95 cm / 37.5 in
Arc'teryx Camosun (Men's)0/-18ReviewNoNoNoParka75010578,750Coreloft140 g/m²N150p-X Gore-TexAround TownTrim960 g / 2 lb 1.9 oz80 cm / 31.5 in
Arc'teryx Cerium SV (Men's)0/-18ReviewNoYesNoDown850162137,700Coreloft80 + 140 g/m²Arato 7 & 10All RoundRegular415 g / 14.6 oz69.5 cm / 27.4 in
Arc'teryx Revet (Men's)2/-17NoNoYesParka750?N/AN/A20d nylon/spandex double weaveAround TownRegular755 g / 1 lb 10.6 oz91 cm / 36 in
Arc'teryx Piedmont (Men's)3/-16NoYesYesParka750218163,500N/AN/AArato 10Around TownRegular515 g / 1 lb 2.2 oz82 cm / 32.25 in
Arc'teryx Fission SV (Men's - Women's)3/-16ReviewNoNoYesSyntheticN/AN/AN/ACoreloft Continuous90 + 65 g/m²N80p-X Gore-Tex 2LAll RoundRegular890 g / 1 lb 15.4 oz81 cm / 31.8 in
Arc'teryx Alpha Lightweight (Men's)3/-16NoYesYesDown85011799,450Coreloft Compact40 g/m²Hadron 2L Gore-Tex InfiniumClimbingRegular540 g / 1 lb 3 oz?
Outdoor Research Sup. Alp. (Men's - Women's)3/-16NoNoYesDown800182145,600N/AN/A30D Pertex Quantum ProAll RoundRegular825 g / 1 lb 13.1 oz85 cm / 33.5 in
Arc'teryx Alessa Long (Women's)3/-16NoNoNoParkaN/AN/AN/ACoreloft80 + 120 g/m²N90p 2L Gore-TexAround TownRegular1.015 kg / 2 lb 3.8 oz123 cm / 48.5 in
Patagonia Tres 3-in-1 (Men's - Women's)3/-16ReviewNoNoNoParka70011882,600N/AN/A5.5 oz polyesterAround TownRegular1.307 kg / 2 lb 14.1 oz85 cm / 33.5 in
Arc'teryx Radsten Parka (Men's)3/-16NoNoNoParkaN/AN/AN/ACoreloft Compact120 g/m²NP100d Gore-Tex 2LAround TownRegular745 g / 1 lb 10.3 oz82 cm / 32.25 in
Rab Electron Pro (Men's - Women's)5/-15NoYesYesDown800180144,000N/AN/A20D Pertex Quantum ProAll RoundRegular525 g / 1 lb 2.5 oz74 cm / 29 in
Arc'teryx Therme Parka (Men's)5/-15ReviewNoNoYesParka75012090,000Coreloft60 + 80 g/m²P75d PolyesterAround TownRegular991 g / 2 lb 3 oz85 cm / 33.5 in
Arc'teryx Macai (Men's)5/-15ReviewYes, zipsNoNoDown7506951,750Coreloft Compact60 + 100 g/m²N40p-X 3L Gore-TexSki/SnowboardRegular1 kg / 2 lb 4 oz76 cm / 30 in
Arc'teryx Nuclei SV (Men's)5/-15ReviewNoYesYesSyntheticN/AN/AN/ACoreloft Continuous180 g/m2 + 90 g/m2Arato 15ClimbingRegular600 g / 1 lb 5.2 oz81 cm / 31.8 in
Patagonia DAS Parka (Men's)5/-15NoYesYesParkaN/AN/AN/APrimaLoft Gold Insulation Eco133 + 40 gPertex Quantum ProAround TownRegular555 g / 1lb 3.6 oz84 cm / 33 in
Arc'teryx Patera (Women's)5/-15ReviewNoNoYesParka7505843,500Coreloft60 + 80 g/m²2L Gore-TexAround TownTrim867 g / 1 lb 14.6 oz93 cm / 37 in
Black Diamond Access Down (Men's - Women's)7/-14NoYesYesDown700155108,500N/AN/A30D ripstop nylonAll RoundRegular442 g / 15.6 oz76 cm / 29.75 in
Arc'teryx Kappa (Men's)7/-14ReviewNoNoYesSyntheticN/AN/AN/ACoreloft Continuous140 g/m²N70p Gore ThermiumAll RoundRegular755 g / 1 lb 10.6 oz80 cm / 31.5 in
Arc'teryx Prema Down Coat (Women's)7/-14NoNoYesParka7509269,000N/AN/ANylonAround TownRegular794 g / 1 lb 12 oz117 cm / 46.1 in
Arc'teryx Radsten Insulated (Men's)7/-14NoNoNoParkaN/AN/AN/ACoreloft Compact120 g/m²NP100d Gore-Tex 2LAround TownRegular715 g / 1 lb 9.2 oz73 cm / 28.75 in
Rab Microlight Alpine (Men's - Women's)7/-14NoYesNoDown700153107,100N/AN/A30D Pertex QuantumAll RoundRegular466 g / 1 lb 0.5 oz72 cm / 28.5 in
Arc'teryx Thorium (Men's - Women's)7/-14ReviewNoYesYesDown750140105,000Coreloft80 + 140 g/m²Arato 30All RoundRegular517 g / 1 lb 2.2 oz71.5 cm / 28.1 in
Feathered Friends Eos8/-13NoYesNoDown90010594,500N/AN/APertex QuantumAll RoundRegular306 g / 10.8 oz?
Arc'teryx Thorium AR (Men's - Women's)8/-13ReviewNoYesNoDown75013097,500Coreloft80 + 140 g/m²Arato 30All RoundRegular490 g / 1 lb 1.3 oz72 cm / 28.3 in
Patagonia Macro Puff (Men's - Women's)8/-13ReviewNoNoNoSyntheticN/AN/AN/APlumaFill135 + 90 g10D Recycled nylon ripstopAll RoundRegular435 g / 15.3 oz79 cm / 31 in
Arc'teryx Macai LT (Men's)8/-13Yes, zipsNoNoDown7504936,750Coreloft Compact60 g/m²N40p-X 3L Gore-TexSki/SnowboardRegular855 g / 1 lb 14.2 oz74 cm / 29.1 in
Arc'teryx Seyla (Women's)8/-13NoNoYesParka7509269,000N/AN/AArato 10Around TownRegular507 g / 1 lb. 1.9 oz.87 cm / 34.4 in
Patagonia Fitz Roy (Men's - Women's)8/-13NoYesNoDown800128102,400N/AN/A20D NylonAll RoundRegular632 g / 1lb 6.3 oz74 cm / 29 in
Arc'teryx Koda (Men's)8/-13NoNoNoParkaN/AN/AN/ACoreloft80 + 140 g/m²N80p-X Gore-TexAround TownRegular720 g / 1 lb 9.4 oz75 cm / 29.5 in
Patagonia Vosque 3-in-1 (Women's)10/-12ReviewNoNoNoParkaN/AN/AN/AThermoLite100 g65% nylon, 35% polyesterAround TownRegular1.360 kg / 3 lb90 cm / 35.5 in
Patagonia City Storm Down (Men's - Women's)12/-11NoYesNoParka700191133,700N/AN/A4.2 oz polyesterAll RoundRegular468 g / 16.5 oz91 cm / 36 in
Patagonia Jackson Glacier (Men's - Women's)12/-11ReviewNoNoYesParka70014198,700N/AN/A3.6 oz 50D polyesterAround TownRegular880 g / 1 lb 15 oz79 cm / 31 in
Arc'teryx Sensa (Women's)14/-10NoNoYesParkaN/AN/AN/ACoreloft Compact120 g/m²NP100d Gore-Tex 2LAround TownRelaxed785 g / 1 lb 11.7 oz86 cm / 34 in
Patagonia Hi Loft Down (Men's - Women's)14/-10ReviewNoYesNoDown600177106,200N/AN/A1.4 oz 30D polyesterAll RoundRegular540 g / 1 lb 3 oz76 cm / 30 in
REI Magma 850 Hoodie 2.0 (Men's - Women's)14/-10NoYesNoDown850120102,000N/AN/APertex mini ripstop nylonAll RoundRegular340 g / 13.75 oz74 cm / 29.25 in
Arc'teryx Beta Insulated Coat (Women's)16/-9ReviewNoNoYesSyntheticN/AN/AN/ACoreloft 80 g/m² + 120 g/m²2L 40D Gore-TexAround TownRegular600 g / 1 lb 5.2 oz?
Arc'teryx Atom AR (Men's - Women's)18/-8ReviewYes, meshNoNoSyntheticN/AN/AN/ACoreloft Continuous120 g/m2 + 80 g/m2 + 60 g/m230D TyonoAll RoundRegular475 g / 1 lb 74 cm / 29.1 in
Patagonia Downdrift (Men's - Women's)18/-8NoNoNoDown600279167,400N/AN/A4.2 oz polyesterAround TownRegular1.014 kg / 2 lb 3.8 oz?
Arc'teryx Magnus (Men's)19/-7NoNoNoParkaN/AN/AN/ACoreloft80 gN60p Gore-Tex 2LAround TownRegular690 g / 1 lb 8.3 oz83 cm / 32.5 in
Arc'teryx Agrium (Men's - Women's)21/-6NoYesNoDown85011799,450N/AN/AAratoAll RoundRegular365 g / 12.9 oz75 cm / 29.5 in
Patagonia AlpLight Down (Men's - Women's)21/-6NoYesNoDown80010080,000N/AN/A0.8 oz 10D polyesterAll RoundSlim270 g / 9.5 oz74 cm / 29 in
Arc'teryx Beta Insulated (Men's - Women's)21/-6ReviewYes, zipsNoYesSyntheticN/AN/AN/ACoreloft Continuous80 g/m²2L 40D Gore-TexAll RoundRegular680 g / 1 lb 8 oz78.5 cm / 31 in
Patagonia Topley (Men's)23/-5NoNoYesDown700172120,400N/AN/A6 oz polyesterAll RoundRegular1.133 kg / 2 lb 8 oz77 cm / 30.5 in
Arc'teryx Alpha IS (Men's)23/-5NoYesYesSyntheticN/AN/AN/ACoreloft Continuous65 g/m²N40p-X 2L Gore-TexClimbingRegular610 g / 1 lb 5.5 oz78 cm / 30.75 in
Rab Xenon 2.0 (Men's - Women's)23/-5NoYesYesSyntheticN/AN/AN/APrimaLoft Silver60 g30D Pertex QuantumAll RoundRegular385 g / 13.6 oz71.5 cm / 28.1 in
Patagonia Down Sweater (Men's - Women's)23/-5ReviewNoYesNoDown800150120,000N/AN/A1.4 oz 20x30D polyesterAll RoundRegular428 g / 15.1 oz67 cm / 26.25 in
Arc'teryx Ralle Parka (Men's)25/-4NoNoYesParkaN/AN/AN/ACoreloft 80 g/m²2L 40D Gore-TexAround TownRegular735 g / 1 lb 9.9 oz?
Patagonia Silent Down (Men's - Women's)26/-3ReviewNoNoNoDown70010976,300N/AN/A2.2 oz polyesterAround TownRegular585 g / 1 lb 4.7 oz74 cm / 29 in
Arc'teryx Therme Insulated (Men's)26/-3ReviewNoNoNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²2L Gore-TexAround TownRegular960 g / 2 lb 1.9 oz73 cm / 28.75 in
Arc'teryx Cerium (Men's - Women's)26/-3NoYesNoDown85011396,050Coreloft 80 + 100 g/m²Arato 15All RoundTrim335 g / 11.8 oz?
Mountain Hardwear GW/2 (Men's - Women's)28/-2NoYesNoDown8008568,000N/AN/A10D Ripstop NylonAll RoundTrim250 g / 8.8 oz70 cm / 27.5 in
Arc'teryx Cerium LT (Men's - Women's)28/-2ReviewNoYesNoDown85010286,700Coreloft 80 + 100 g/m²Arato 10All RoundTrim305 g / 10.8 oz72 cm / 28.3 in
Arc'teryx Nuclei FL (Men's - Women's)32/0ReviewNoYesNoSyntheticN/AN/AN/ACoreloft Continuous65 g/m²Arato 10rClimbingTrim325 g / 11.5 oz75 cm / 29.5 in
Patagonia DAS Light (Men's - Women's)34/1NoYesYesSyntheticN/AN/AN/APlumaFill65 g0.8-oz 10-denier Pertex Quantum ProClimbingRegular320 g / 11.3 oz77 cm / 30.5 in
Patagonia Micro Puff (Men's - Women's)36/2ReviewNoYesNoSyntheticN/AN/AN/APlumaFill65 gPertex QuantumAll RoundTrim298 g / 10.5 oz75 cm / 29.5 in
Patagonia Isthmus (Men's)36/2NoNoNoParkaN/AN/AN/AThermoGreen60 g4.2 oz polyesterAround TownRegular895 g / 1 lb 15.6 oz70 cm / 27.5 in
Arc'teryx Proton LT (Men's - Women's)37/3ReviewNoNoNoSyntheticN/AN/AN/ACoreloft Compact80 g/m2 + 60 g/m2Fortius Air 20ClimbingTrim375 g / 13.2 oz75 cm / 29.4 in
Patagonia Nano Puff (Men's - Women's)37/3ReviewNoYesNoSyntheticN/AN/AN/APrimaLoft Gold Insulation Eco60 g22D PolyesterAll RoundRegular363 g / 12.8 oz71.5 cm / 28 in
Arc'teryx Norvan SL Ins. (Men's - Women's)39/4NoYesNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²Gore-Tex ShakeDryRunningTrim270 g / 9.5 oz71.5 cm / 28.1 in
Patagonia Nano Air (Men's - Women's)41/5ReviewNoNoNoSyntheticN/AN/AN/AFullRange60 g33D Nylon ripstopAll RoundTrim318 g / 11.2 oz?
Arc'teryx Atom LT (Men's - Women's)43/6ReviewYes, meshNoNoSyntheticN/AN/AN/ACoreloft Continuous60 g/m²20D TyonoAll RoundTrim375 g / 13.2 oz74 cm / 29.1 in
Arc'teryx Cerium SL (Men's - Women's)43/6ReviewNoYesNoDown8505849,300Coreloft 40 + 100 g/m²Arato 7All RoundTrim215 g / 7.6 oz69 cm / 27.2 in
Arc'teryx Proton Hybrid (Men's - Women's)46/8ReviewNoNoNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²Fortius™ Air 50All RoundTrim365 g / 12.9 oz?
Arc'teryx Proton FL (Men's)48/9ReviewNoNoNoSyntheticN/AN/AN/AOcta Loft94 g/m²Fortius Air 20ClimbingTrim323 g / 11.4 oz77 cm / 30.4 in
Arc'teryx Atom SL (Men's - Women's)52/11ReviewYes, meshNoNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²20D TyonoAll RoundTrim245 g / 8.6 oz72 cm / 28.3 in
REI Stormhenge Hybrid (Men's - Women's)TestingYes, zipsNoNoDown850?N/AN/A40D + 80DAll RoundRegular900 g / 1 lb 15.75 oz80 cm / 31.5 in
Arc'teryx Monitor Insulated (Women's)TestingNoNoYesParkaN/AN/AN/ACoreloft80 + 100 g/m²40D 3L Gore-TexAround TownOversized645 g / 1 lb 6.8 oz93 cm / 37 in
Arc'teryx Coelle (Women's)TestingNoNoYesParkaN/AN/AN/ACoreloft80 + 140 g/m²40D 2L Gore-TexAround TownRegular460 g / 1 lb 0.2 oz93 cm / 37 in

As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%. I explained why this happens here in this post of mine. 

These are only approximate values assuming:

  • you only have a shirt under and no shell over,
  • during daily use (strolls, power walks etc at most - no high output activities), 
  • with enough wind to cause an umbrella to twist in your hand, 
  • and when it's dry out.

If you think you run warmer or colder than the average person, then shift temperature ranges accordingly.

Also see: 

Proton LT (see image) is the most durable of all. It's also one of my favorite jackets. 

Breathability

Although Atom LT delivers the membrane with the least breathable of these 3, it certainly still offers the most total breathability of all because of its mesh ventilation panels located at the arm pits. 

Mechanical ventilation will almost always be a superior parameter than membrane breathability. 

 

Warmth & Weather Resistance

Side fleece panels of Atom LT become a disadvantage when it's cold, windy and/or rainy. They'll let some foul weather in. 

On top of that, Proton LT offers 80 gsm of Coreloft reinforcements in strategical areas such as the hood, in addition to 60 gsm in the body. Atom LT, on the other hand, is equipped with 60 gsm everywhere, without any reinforcements.

This makes Proton LT the warmest of all. 

When it comes to weather resistance, Proton LT again takes the lead thanks to its stiffer and relatively more robust face fabric. Nano Air is the most fragile of all, so it's going to offer the least amount of weather protection in this regard. Not only against precipitation but also against wind. 

Also, all these jackets are DWR coated. 

  • What is DWR by the way?

DWR is a coating. 

It's basically sprayed on to the surface of these jackets as a finish. It stands for Durable Water Repellent - which means that water will be repelled under wet conditions instead of soaking into the fabric. 

DWR also decreases dry time. 

It's a good thing these jackets are coated in DWR, but pay attention to the fact that DWR is a coating - meaning that it will wear off over time. 

Which is why you might want to invest in a DWR spray such as this one for after treatment. 

As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%. I explained why this happens here in this post of mine. 

Packability

Air is packable whereas the Atom LT and Proton LT aren't. 

Links:

I hope this post was helpful for you to learn more about the jacket(s) in your mind.


Feel free to ask me any questions or provide feedback and I'll be happy to respond in the comment section below.


Guide: Insulated & Shell Jackets

Start here:

Complete list:

Synthetic Insulated Jackets

Down Jackets

Parkas

Shell Jackets

Ski Jackets

Fleece Jackets

Wind Jackets

Rain Jackets

Also see:

Thank you for reading!

Reader Interactions

Comments

  1. Jeff Roe says

    Which of the 3 jackets would you recommend for cycle touring? I’m riding my bicycle ~20,000 miles the length of the America’s starting next summer and am looking for a nice warm riding jacket that will breathe well. Was leaning towards Proton or Nano Air. Any guidance?

    Cheers,
    Jeff