The Proton LT Hoody is Arc’teryx’s lightweight version of durable mid or outer layer depending on the weather. It does this job very well indeed.

Arc’teryx have various naming conventions for different uses such as MX, SL, FL, LT, AR and SV. The Proton with its LT naming means its focus is on lightweight and to be used when you’re moving or putting out a lot of energy such as climbing, skinning uphill, or climbing.

Design, Comfort & Durability (Rating: 80%)

Arc’teryx gear is well known in the outdoor community and for good reason, they make some high-quality clothing. The Proton LT Hoody is slightly updated from their previous versions, mainly with an increase in the amount of elastane and a slight increase in insulation content. The Proton LT has breathable insulation which allows heat and moisture to pass through while still maintaining great insulative capability. There are other more breathable insulators around but the Proton LT has some unique features that set it apart from the others.

The Proton LT is designed to be either a mid-layer or outer layer depending on conditions and is a great replacement for a thick softshell as its lighter weight and good weather resistance capabilities mean you can be pretty sure you’re able to stay warm in changing conditions while still having breathability. I tend to run a bit cold when doing things and I thought I’d be a little cold in this lightweight jacket but it provided enough insulation to keep me quite warm.

The jacket held its own while testing in windy and rainy conditions. I felt quite comfortable in high winds although I could feel the wind getting in, it didn’t take away all my heat or cut through like wind does when wearing a non-windproof jacket. While this doesn’t sound great it was quite comfortable standing around in the cold and wind while belaying friends at some supposedly out of the wind crags.

When it was very gusty the wind resistance of the jacket fell through, but that’s what hard-shells are for. The conditions I used the jacket in, the jacket had enough wind resistance to keep me warm while moving and was breathable enough to stop me from sweating or getting clammy if standing around. The jacket kept me warm enough in the morning while the temperature was still just around zero as well which was nice.

A great feature of the jacket is the hood which can accommodate a climbing helmet and has a decent cinch cord so that if you’re not wearing the helmet it will stay in place while moving or in windy conditions. There is no peak on the hood so bear that in mind if you like to have a peak on your hoods. Instead of a peak, the hood is volume adjustable at the back. Now while the hood was great with a helmet on, without you needed to pull the cinch cord in tight at the back, which wasn’t that much of a problem once done.

The cinch cord is great and locks on the hem are fantastic, you barely notice the hemlocks and they are out of the way facing into the jacket making snagging on things unlikely. The added elastane to the more durable outer layer makes the jacket quite comfortable to wear, providing a full range of motion and allowing the sleeves to be pulled up if needed.

Arc'teryx Proton LT Hoody
The jacket isn’t the most lightweight of insulators (it’s not exactly heavy either at ~380g) but it is much harder wearing than a comparable similar offering such as lightweight puffers from Patagonia, Rab, or The North Face. Some lightweight puffers tend to disintegrate when being put through the same amount of abrasive testing as the Proton LT was. I wore it both while belaying and climbing and often was scraping across the cliff face with the jacket. The hard-wearing outer layer of the jacket had no problem dealing with this kind of abuse. Try that with a lightweight puffer and you’d probably end up a feathery mess by home time.

While the jacket excels with abrasion against rock and other hard surfaces, watch out in the Australian scrub as getting jagged with a tree branch or similar may end up putting a hole through the jacket. In my experience this can occur with any jacket but worth noting if you’re an off-track bushwalker or similar. I did bushwalk a little in this jacket and most plant

Packing down the jacket is relatively easy however it doesn’t come with its own self-packing pocket so you would need a stuff sack or similar to stow it away, it ends up about the size of a rockmelon, possibly a little smaller. I usually just stuff them into my backpack anyway and it was really easy to do.

As always, pocket design is rather important especially if you’ll be wearing either a climbing harness, a backpack harness or both. The Proton LT gets this almost right – the pockets are just out of the way of a harness and it has enough pockets to keep hands warm and a chest pocket with zip to stow a phone or similar near the body, but not much else as the chest pocket is rather slimline.

Functionality & Ease of Use (Rating: 80%)

As with most Arc’teryx clothing, the fit is exceptional. The arms and body length are spot on and moving or reaching doesn’t result in exposed bits of skin to the elements while scrambling or climbing. The main zipper on the Proton LT is a durable and thick YKK zipper which is decently sized and durable.

If your activity requires gloves the sleeves of the Proton LT have a nice cuff that will slip over thinner first layer gloves while allowing bulkier gloves to slide over the top.

In the right weather conditions, the Proton LT can be left on when standing around and also while climbing or being active as the breathability is amazing. I didn’t find I needed to shed the Proton LT when transitioning from belaying to climbing, it both kept me warm and didn’t let me overheat while being active. The outer layer is surprisingly water resistant and tolerated an unexpected heavy downpour while out walking, the DWR layer repelled the water and it would take quite a bit of water to get through to the insulation layer.

During testing, none of the stitching frayed or came undone. You also can’t tell that I’ve been scraping it across rock faces and tree trunks while climbing, canyoning and abseiling which is amazing. The other plus is the Proton LT hoody looks pretty good to just wear around town if needed.

Overall this is a great lightweight hooded insulation layer that can be used to replace a softshell, which is how I use it now. While not the lightest weight option around it doesn’t weigh much more than competitors such as the Patagonia Nano puffer and provides a level of wear resistance and weather resistance that you may not get with other similar jackets. You could also be confident that the Proton LT would function as a standalone warm layer if the conditions were going to be fairly stable and not too windy, wet or cold.

What I Like

  • Fit
  • Breathability
  • Weather resistance and weight

What I Don’t Like

  • Hood on without a helmet – no peak means it needs to be adjusted
  • Could pack down a little better but it’s not a major concern

Get One

The Arc’teryx Proton LT Hoody is available online from Wild Earth.
Disclaimer: Arc’teryx provided a hoody for review. The above Wild Earth link is an affiliate link. None of this has any influence on the opinions presented in the above review.
Have you tried the Arc’teryx Proton LT Hoody? Got any questions or comments? Let us know by commenting below.