Going from top to bottom (Atom SL, LT and AR respectively), the warmth increases and the breathability decreases.
Compared to my other articles on Arc'teryx and Patagonia jackets, this comparison is relatively easier to get out of. Because they differ clearly in this one manner:
How you're planning to use the jacket.
So I'd recommend you to move forward considering this:
If you're looking for a warm jacket to put on out in the town when it's freezing (below 20 deg F's), get the AR (because the LT won't cut it). For a physically active use, get the LT as it's significantly more breathable and comfortable.
You can also see this on Arc'teryx's own Naming Scheme Page here, for both Atom AR and the LT.
- #A sidenote here: Arcteryx.com's PDF guide to their jackets is GOOOLLDDD. Highly recommend you to check it out before you buy.
They're given a dope-dyed liner, a new construction on the cuff and are now 1" (2.5 cm) longer.
But these updates pretty much don't cause any differences in practice. Which means that you can apply the information given in this post to previous revisions of these jackets.
All the differences between these jackets can simply be listed as follows:
- LT is more breathable, lighter and more comfortable
- AR is much warmer and more weather resistant
We'll get to the details and determine how MUCH one is better than the other in terms of each and every one of these differences - but you should know that for most of you the answer to it wouldn't be that important.
Because, like I said, it's like comparing apples and oranges. The purpose of these jackets are different, and this should be your main focus. Keep that in mind as you read on.
- Some of the Arc pieces you see in this post might be discontinued, and hence might be unavailable at arcteryx.com.
- If that's the case, then I'd recommend you to check out this page at REI. You might be able to find them there.
Here's the list of the lowest temperatures you can wear each Arc'teryx jacket without feeling uncomfortably cold.
Keep in mind that these are only approximate values assuming:
- worn over a shirt only and no shell over,
- during daily use (strolls, power walks etc at most - no high output activities),
- with light wind,
- and when it's dry out.
| Name | Est. Temp (F/C) | Insulation | Review | |||
|---|---|---|---|---|---|---|
| Arc'teryx Alpha Parka (Men's - Women's) | -17/-27 | Down | Down | No | M | |
| Feathered Friends Khumbu (Men's) | -17/-27 | Down | Down | No | M | |
| Arc'teryx Ceres SV (Men's - Women's) | -15/-26 | Down | Down | Review | Yes | M |
| Mountain Equipment K7 (Men's - Women's) | -13/-25 | Down | Down | No | M | |
| Rab Positron Pro (Men's - Women's) | -13/-25 | Down | Down | No | M W | |
| Patagonia Grade VII (Men's) | -11/-24 | Down | Down | No | M | |
| Arc'teryx Firebee AR (Men's - Women's) | -10/-23 | Down | Down | Review | Yes | M W |
| Mountain Equipment Exo (Men's) | -10/-23 | Down | Down | No | M | |
| Arc'teryx Thorsen (Men's) | -7/-22 | Down | ParkaD | Review | No | M |
| Patagonia Frozen Range (Men's - Women's) | -6/-21 | Down | ParkaD | Review | No | M W |
| Arc'teryx Centrale (Women's) | -5/-20 | Down | ParkaD | Review | No | W |
| Rab Neutrino Pro (Men's - Women's) | -2/-19 | Down | Down | No | M W | |
| Arc'teryx Therme (Men's) | -2/-19 | Down | ParkaD | Review | No | M |
| Arc'teryx Dually Belay (Men's) | 0/-18 | Synthetic | Synthetic | Review | Yes | M |
| Arc'teryx Camosun (Men's) | 0/-18 | Down | ParkaD | Review | No | M |
| Arc'teryx Piedmont (Men's) | 2/-17 | Down | ParkaD | No | M | |
| Arc'teryx Fission SV (Men's - Women's) | 3/-16 | Synthetic | Synthetic | Review | No | M |
| Outdoor Research Super Alpine (Men's - Women's) | 3/-16 | Down | Down | No | M W | |
| Patagonia Tres 3-in-1 (Men's - Women's) | 3/-16 | Down | ParkaD | Review | No | M W |
| Arc'teryx Radsten (Men's) | 3/-16 | Synthetic | ParkaS | No | M | |
| Patagonia Fitz Roy (Men's - Women's) | 3/-16 | Down | Down | No | M W | |
| Rab Electron Pro (Men's - Women's) | 5/-15 | Down | Down | No | M W | |
| Arc'teryx Macai (Men's | 5/-15 | Down | Down | Review | No | M W |
| Arc'teryx Nuclei SV Parka (Men's - Women's) | 5/-15 | Synthetic | Synthetic | No | M W | |
| Patagonia DAS Parka (Men's - Women's) | 5/-15 | Synthetic | ParkaS | No | M W | |
| Arc'teryx Patera (Women's) | 5/-15 | Down | ParkaD | Review | No | W |
| Arc'teryx Cerium SV (Men's - Women's) | 7/-14 | Down | Down | Review | Yes | M W |
| Black Diamond Access Down (Men's - Women's) | 7/-14 | Down | Down | No | M W | |
| Arc'teryx Kappa (Men's - Women's) | 7/-14 | Synthetic | Synthetic | Review | Yes | M |
| Arc'teryx Prema (Women's) | 7/-14 | Down | ParkaD | No | W | |
| Arc'teryx Radsten Insulated Men's) | 7/-14 | Synthetic | ParkaS | No | M | |
| Rab Microlight Alpine (Men's - Women's) | 7/-14 | Down | Down | No | M W | |
| Patagonia Macro Puff (Men's - Women's) | 8/-13 | Synthetic | Synthetic | Review | No | M W |
| Feathered Friends Eos (Men's - Women's) | 8/-13 | Down | Down | No | M W | |
| Arc'teryx Macai LT (Men's) | 8/-13 | Down | Down | No | M | |
| Arc'teryx Seyla (Women's) | 8/-13 | Down | ParkaD | No | W | |
| Arc'teryx Koda (Men's) | 8/-13 | Synthetic | ParkaS | No | M | |
| Arc'teryx Thorium AR (Men's - Women's) | 8/-13 | Down | Down | Review | No | M W |
| Arc'teryx Kole (Men's - Women's) | 10/-12 | Down | ParkaD | No | W | |
| Patagonia Vosque 3-in-1 (Women's) | 10/-12 | Synthetic | ParkaS | Review | No | W |
| Arc'teryx Alpha IS (Men's - Women's) | 12/-11 | Synthetic | Synthetic | Yes | M | |
| Patagonia Jackson Glacier (Men's - Women's) | 12/-11 | Down | ParkaD | Review | No | M W |
| Arc'teryx Sensa (Women's) | 14/-10 | Synthetic | ParkaS | No | W | |
| Patagonia Hi Loft Down (Men's - Women's ) | 14/-10 | Down | Down | Review | No | M |
| REI Magma 850 Hoodie 2.0 (Men's - Women's) | 14/-10 | Down | Down | No | M W | |
| Arc'teryx Atom AR (Men's - Women's) | 18/-8 | Synthetic | Synthetic | Review | No | M W |
| Patagonia Downdrift (Men's - Women's) | 18/-8 | Down | Down | No | M W | |
| Patagonia Down Sweater (Men's - Women's) | 19/-7 | Down | Down | Review | No | M W |
| Arc'teryx Magnus (Men's) | 19/-7 | Synthetic | ParkaS | No | M | |
| Arc'teryx Agrium (Men's - Women's) | 21/-6 | Down | Down | No | M W | |
| Patagonia AlpLight Down (Men's - Women's) | 21/-6 | Down | Down | No | M W | |
| Patagonia Topley (Men's) | 23/-5 | Down | Down | No | M | |
| Rab Xenon 2.0 (Men's - Women's) | 23/-5 | Synthetic | Synthetic | No | M W | |
| Patagonia Silent Down (Men's - Women's) | 26/-3 | Down | Down | Review | No | M W |
| Mountain Hardwear Ghost Whisp/2 (Men's - Women's) | 28/-2 | Down | Down | No | M W | |
| Arc'teryx Cerium LT (Men's - Women's) | 28/-2 | Down | Down | Review | No | M W |
| Arc'teryx Nuclei FL (Men's - Women's) | 32/0 | Synthetic | Synthetic | Review | No | M W |
| Patagonia City Storm Down (Men's) | 32/0 | Down | ParkaD | No | M | |
| Arc'teryx Atom LT (Men's - Women's) | 36/2 | Synthetic | Synthetic | Review | No | M W |
| Patagonia Micro Puff (Men's - Women's) | 36/2 | Synthetic | Synthetic | Review | No | M W |
| Patagonia Isthmus (Men's | 36/2 | Synthetic | ParkaS | No | M | |
| Arc'teryx Proton LT (Men's - Women's) | 37/3 | Synthetic | Synthetic | Review | No | M W |
| Patagonia Nano Puff (Men's - Women's) | 37/3 | Synthetic | Synthetic | Review | No | M W |
| Arc'teryx Norvan SL Ins. (Men's - Women's) | 39/4 | Synthetic | Synthetic | Yes | M W | |
| Patagonia Nano Air (Men's - Women's) | 41/5 | Synthetic | Synthetic | Review | No | M W |
| Arc'teryx Cerium SL (Men's - Women's) | 43/6 | Down | Down | Review | No | M W |
| Arc'teryx Proton FL (Men's - Women's) | 48/9 | Synthetic | Synthetic | Review | No | M W |
| Arc'teryx Atom SL (Men's - Women's) | 52/11 | Synthetic | Synthetic | Review | Yes | M W |
| The North Face Summit Down (Men's - Women's) | Testing | Down | Down | No | M W | |
| Mountain Equipment Lightline Echo (Men's) | Testing | Down | Down | No | M | |
| Mountain Equipment Kryos (Men's - Women's) | Testing | Down | Down | No | M W | |
| Mountain Equipment Xeros (Men's - Women's) | Testing | Down | Down | No | M | |
| Arc'teryx Andra LT IS (Women's) | Testing | Synthetic | ParkaS | No | W | |
| Arc'teryx Phoria IS (Women's) | Testing | Synthetic | ParkaS | No | W | |
| Feathered Friends Helios (Men's) | Testing | Down | Down | No | M | |
| Feathered Friends Volant (Men's) | Testing | Down | Down | No | M | |
| Rab Axion Pro (Men's - Women's) | Testing | Down | Down | No | M W | |
| Feathered Friends Rock & Ice (Men's) | Testing | Down | Down | No | M | |
| Rab Valiance (Men's - Women's) | Testing | Down | Down | No | M W | |
| Rab Expedition 8000 (Men's) | Testing | Down | Down | No | M | |
| Rab Zero G (Men's) | Testing | Down | Down | No | M | |
| Rab Generator Alpine (Men's) | Testing | Synthetic | Synthetic | No | M | |
| UBR Regulator Parka II (Men's) | Testing | Synthetic | ParkaS | No | M | |
| Helly Hansen LifaLoft (Men's - Women's) | Testing | Synthetic | Synthetic | No | M | |
| Mammut Eigerjoch (Men's - Women's) | Testing | Synthetic | Synthetic | No | M W | |
| Helly Hansen Lumines (Men's - Women's) | Unknown | Synthetic | Synthetic | No | M | |
| Haglofs V Series Mimic (Men's - Women's) | Unknown | Synthetic | Synthetic | No | M W | |
| Black Diamond First Light (Men's - Women's) | Unknown | Synthetic | Synthetic | No | M W |
Liked this table?
If you did, check out this post of mine to see more Arc'teryx tables like this one, such as fill details for all down jackets.
I've also put this post together to compare and rate all the popular synthetic insulated jackets, including the two in this post (as well as the Proton LT I mentioned).
So if you're interested to see how well these two jackets scored in the warmth, comfort, weather & abrasion resistance, breathability and style departments; you might want to check that out as well.
Let's get to it!
Warmth
I'm not going to explain the Coreloft insulation in detail because both jackets are equipped with it. I'll try to keep this post within the context of differences between these products.
Check this thread out if you're curious about Coreloft's technical properties and how it compares to the other insulators.
First of all, the AR does NOT have twice the insulator amount of LT.
AR is insulated with:
- 120 g/m2 of Coreloft around the torso: This is the only region AR doubles the insulator amount of LT.
- 80 g/m2 of Coreloft under the arms: They're mostly compressed anyway. Investing less insulator here not only decreases the price but also increases mobility.
- 60 g/m2 of Coreloft for the hood.
LT, on the other hand, is insulated with 60 g/m2 of Coreloft everywhere.
This makes up one of the biggest differences between the two models:
AR is significantly warmer compared to LT. If you're truly active inside the AR, you might even overheat.
Now, although it's quite difficult to pinpoint the warmth differences between these two jackets, let me do my best and at least try to give you an idea:
Generally speaking, with only a long sleeved shirt under and without a shell on top, for an average person, during daily use (strolls, power walks, etc) and with enough wind to cause an umbrella to twist in your hand:
...without feeling uncomfortably cold, the lowest temperature to wear an Atom LT would be 36 deg F (2 deg C), and Atom AR around 18 deg F (-8 deg C).
With at least a moderate quality layering:
...Atom LT would be at 25 deg F (-4 deg C), and AR at 7 deg F (-14 deg C).
With a good base layer under and a shell jacket on top:
...Atom LT would be at 10 deg F (-10 deg C), and AR at -4 deg F (-20 deg C).
Note that AR can even come too warm when you near 40 F's.
Maybe this entire thing can be oversimplified into this:
If you're looking for a warm jacket to put on out in the town when it's freezing with shitty wind, do not get an LT! You'll probably feel too cold inside it!
Although it breathes poorly, AR is much warmer and wind resistant - which makes it excellent for stationary use.
Wind & Water Resistance
Although side fleece panels of LT make it much more breathable, it sacrifices wind resistance significantly.
Although both these jackets are marketed as mid layers (meaning you need an extra layer over them), with the AR, you won't need a shell unless there's heavy rain.
With the LT, though, you probably will.
Speaking of rain, both jackets come with DWR coating at the top - although they're mid layers.
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.
So the winner is AR by far.
Side panels help LT breathe perfectly during skiing as well as any other activity that requires high mobility.
Breathability
Until this point, I've repeated it many times, but for the sake of consistency let me say it one more time:
LT is much more breathable than AR due to its side fleece panels.
This is also what causes AR to overheat much easier compared to LT.
If you're active, OR it's nearing 30 F's out, AR probably will start feeling too warm, even if it isn't layered with anything else.
That said, LT still isn't the BEST in terms of breathability.
I don't want to confuse you even further, but note that in our post Patagonia Nano Air vs Arcteryx Atom LT, we found that the Air is actually more breathable - although less weather resistant and more, ugh, "frumpy" looking.
Fit and Comfort
First of all, LT comes with a trim fit and AR with a regular fit. If you have an athletic build, LT would probably look very good on you. AR, on the other hand, is more "bulky".
If you'd like to see some numbers:
Atom LT Hoody (Medium)
- Chest: 117.5 cm
- Waist: 109.5 cm
- Back Length: 74 cm
- Sleeve Length: 91.5 cm
Atom AR Hoody (Medium)
- Chest: 120.5 cm
- Waist: 112.5 cm
- Back Length: 74 cm
- Sleeve Length: 91 cm
Note: The small sizes are roughly 5 cm smaller in the chest and waist.
This is how Trim and Regular Fits are illustrated by Arcteryx:
Men's fit. LT comes with a trim fit and AR with a regular fit.
Women's fit. LT comes with a trim fit and AR with a regular fit.
Another thing about fit is that AR is thicker and more puffy going outwards:
That said, the "puffiness" difference isn't big enough to cause a difference when you're trying to layer a shell on top.
Weight
At 0.9 lbs (415 grams), LT is only 0.1 lbs lighter compared to AR's 1 lb (470 grams) of weight.
If you'll be wearing the jacket out in the town only, this won't be a noticeable difference.
However, for activities that require physical strength and endurance, this difference will make a difference for most of us.
Versatility
You can use LT pretty much doing any outdoor activity, such as:
- Skiing,
- Snowboarding,
- Trekking,
- Mountaineering,
- Fishing,
- Climbing,
- Biking,
- Snowshoeing,
- Surfing (kidding).
You name it.
*Biking & rocking LT's.
On the other hand, AR would be too warm and uncomfortable for all of these activities. It'd be more suitable for casual, frigid weather outgoings, though.
They're even marketed that way by Arcteryx themselves.
So I don't thing we can say one is more versatile than the other, since one can't replace the other's work. Just choose according to your own needs and desires.
Conclusion
So... in short:
If you're going to be physically active, absolutely get the Atom LT since it's more breathable. For a stationary use, absolutely get the Atom AR since it's warmer and more weather resistant.
Trekitt's reviews on these jackets also worth checking out:
Atom AR:
Atom LT:
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:
Also see:
Thank you for reading!
Great page, really digging how comprehensive your info is! I’m in the market for a new winter jacket and am torn on what to get. I’ve narrowed myself down to the Fission for the extremely windy and harsh cold and wind, and considering getting an Atom AR for when it’s not as frigid and less windy, which I could also use for hiking and other high output activities since it is packable if I get too warm. I looked at the Atom LT originally, but since I tend to be on the colder side, I figured I should go AR instead of LT. And now that I’ve discovered the Proton LT, i’m torn between Proton LT vs. Atom AR.
Thank you for the kind words Josh! Glad it’s helpful for you 🙂
Could you elaborate the approximate lowest temperatures you’re planning to wear your jacket? Note that the Proton LT isn’t warmer than Atom LT – in fact, it’s even a little bit colder.
Really love your Arc’teryx guides. Very practical and to-the-point info. I recently got the Atom AR (my first insulated jacket) and it fits my needs perfectly. I use it when walking my dog or around town at temps between 20f and 40f with just a t-shirt underneath (haven’t had a chance to try it in colder temps than that). One thing I really like about it is that the hood is made to fit over a helmet which means I can comfortably wear my over-the-ear headphones with the hood on- that’s a feature I didn’t even realize I needed! I considered the Atom LT but ultimately warmth was more important than breathability for my uses.
Outstanding!
Thank you very much for all that info. It really helps me a lot to decide on what jacket is best for me.
I’m tying myself in nots trying to decide between the LT and the AR, and reading the various articles and reviews is helping and also adding more confusion at the same time. Obviously when you’re spending this amount of money on a jacket you want to get the right one!!
I’m looking for a multi purpose jacket that I can use around town in the autumn and winter months, wear to the park with my daughter and then go on family walks and outings. So temperatures will range from 30 degF (0 degC) to 50-55 degF (10-12C). The activity will be a range of walking and probably standing around
Any help and advice would be massively appreciated
I’d recommend getting the LT in this case, Simon. It actually would work perfect in this setting. You’re likely to overheat inside the Atom AR.
Oh I was thinking you’d say. AR
Hi, just a note to say that I really enjoyed reading this review and content. It’s full of information, but is so well structured that it’s not overwhelming.
You’ve pulled in comparable products, with both useful context and relevance. For someone who knew of, but not about Arcteryx products, this has given me the knowledge and confidence to buy the model that I was interested in (LT).
I’m sure many visitors don’t appreciate the work and time that you have put into this page, so hopefully this little nod of appreciation is welcome. I wouldn’t normally take the time to write something like this, but I think you’ve done a fantastic job on this site, and think it sets the gold standard for how products should be reviewed! Keep it up and thank you!
Thank you so much Steven. I really appreciate your kind words. Glad I was helpful. Thank you for taking the time to write this comment.
I would like to second that. I always come here for advice. Thank you for your effort. Cheers!
Thanks for all the resources here. I recently purchased the Camosun and really, really like the build quality. I live in the Midwest of the US and am starting to worry it’s going to be over engineered for me. I was looking for something that could withstand snow and wind (if I’m outside shoveling for example). That being said, I’m usually driving to work. I’m just outside on walks with the family or around town casually. Thinking about swapping out for the Atom AR. What are your thoughts?
In case anyone finds this and are in the same boat: I’m definitely keeping the Camosun. I would be interested in picking up an Atom LT in the future for not so cold days, but the Camosun has been a beast in the recent cold and snowy weather.
Great resource, thank you
I’m still torn between the Atom AR and LT.
Firstly, I live in the UK so the temperatures are rarely below -5c and I would probably wear it up to about 15c
The reason for my indecision is my usage is varied; I would use it for photography where I’m hiking into/up to a location, carrying a large pack and tripod, so raising a good old sweat. And then I would be pootling around on location for an hour or so, getting cold.
I’d also wear it for commuting (flipping between cold railway platforms and stuffy trains).
I’m replacing my Mountain Equipment Bastion jacket, which has been fantastic down the years, so something approaching this would be perfect.
I can see benefits in both models, but would really appreciate your insight.
Thanks
Hi thanks for your detailed review!
I was just wondering what your thoughts were regarding a jacket whose main use would be cold-weather cycling – these being two I am considering. I live in Toronto so we get decently cold winter days, with average winter temperatures (incl. wind chill) around -10C (14F). As it stands I have a thick parka for the really cold winter days where biking isn’t an option, but for the temperatures down to -15C I still bike and so I need something that’s not a heavy parka for this.
I was initially thinking of getting the Atom LT when it came on sale next season for the 15C to 0C temps, and then either the Patagonia Jackson Glacier or new Downdrift Jacket for the 0C to -15C temps. However I recently learned about the Atom AR and so that interested me as the jacket for the 0C to -15C temps. One thing I’m wondering is if your breathability/overheating concerns would even apply to me if I were using it below 0C. Also will you review the new Arcteryx Agrium and Patagonia Downdrift (as these are big alternatives I am considering)?
Thanks!