Arc'teryx Kyanite Lightweight Hoody Review

The Kyanite Lightweight has a high proportion of elastane, making it super comfortable and stretchy. It fits well over a base layer and under another fleece or a shell. Even with a slim fit, its gusseted armpits ensure there is enough room inside this featherlight fleece.

Performance Comparison

Warmth

The Kyanite Lightweight Hoody is warmer than we would have expected. With a long sleeve base layer underneath, it is reliably warm to about 45 °F during moderate activity. We also appreciate that the zipper is skinny enough that the wind doesn't cut through it and penetrate your core. The tight-weave fabric is more insulating than the grid fleece of other hoody models (though there are also implications for breathability, discussed below).

In fact, given the stretchiness of the fabric, we were surprised by how wind-resistant this fleece is. Add in a high neck and a form-fitting hood and this jacket punches far above its weight class in terms of warmth. There were several times when we were skeptical that the hood was contributing in any significant way to heat retention, only to find upon pulling it down that it was actually doing a lot of work.

Our only complaint about the warmth of this model is that it really isn't very long, and even our base layers sometimes peeked out from the bottom. We especially noticed this when reaching or stretching upward, which pulled up the bottom of the fleece above the waist of our pants, exposing bare skin to the elements.

Comfort

The fabric blend of 84% polyester and 16% elastane makes for a super stretchy jacket. However, it is worth noting that this jacket has a slim fit and a short cut, stopping just below where a pant waist begins. Though its shorter sleeves can ride up when reaching overhead, we appreciate that the stretch of the arms doesn't limit mobility. The fleece is not as plush as many other models, but it's still soft on the inside. This is especially important in the hood, where our skin is often in direct contact with the fabric. We didn't experience any chaffing in cold weather and the hood stayed on securely enough to move with our head and neck rotation, which is not often the case with any jacket.

The zippered hand pockets are mesh-lined, and carrying heavier items like a smartphone feels clunky. Despite the lightweight design, the pockets are still sufficient for holding keys or small snacks like a protein bar. But we couldn't figure out why the interior pocket liner isn't sewn shut at the bottom. This wouldn't add any extra weight but could effectively create two interior drop pockets.

There are, however, a few subtle touches that really add to the overall comfort of this hoody. The zipper is narrow enough that the two sides come together completely on the interior of the garment, leaving no room for a freezing metal zipper to touch a bare chin when fully zipped. More for the comfort of our partners, the claimed anit-odor finish seems to do its job: we didn't notice any lingering trail smell, even after a two-month trek without washing this jacket.

Breathability

Despite the weight of this jacket, it really isn't a contender when it comes to breathability. The thinner, stretchy material vents well enough, and the full zipper ensures that you can always dump excess heat. Thanks to the slim fit, the sleeves also stay up if you pull them above your elbows.

Having said that, the Kyanite can't compete with the gridded fabric of other, more breathable fleeces we tested it against. Although no fleece feels truly breathable during high-exertion activities, this jacket performs much better than other mid- and heavyweight crew jackets in the lineup. We experienced far less overheating panic in this jacket than any of those other models.

Layering Ability

This jacket is an excellent standalone outer layer for cool, breezy weather. Though the brushed fleece bunches a bit when pulling it on, this jacket does fit well over a long-sleeved base layer and integrates nicely into a more comprehensive layering system.

It is slim-fitting enough to add another mid-layer on top, but also warm enough that in many cases we were comfortable wearing this jacket with just a waterproof shell over top. The upside of its shorter length is that it never sticks out from underneath a rain jacket, keeping it dry even in the worst weather.

The hood is also quite versatile. It is tight enough to stay up securely on its own but also stretchy enough to fit comfortably over a wool hat. Similarly, it nests seamlessly into a rain jacket hood and can be pulled up even when fully zipped, which other hoody models sometimes cannot do.

Weight

Weighing in at 10.9 ounces, this is one of the lightest fleece jackets we have ever tested. And even though it packs down small, it is warmer than it looks.

For this reason, this fleece is one of our favorites for long-distance adventures, where every ounce matters. Its thin fabric fits comfortably underneath a backpack hip belt without bunching up, and it fits easily in many exterior pockets for easy access – we often kept ours in the mesh pocket on the back of the pack.

Should You Buy the Arc'teryx Kyanite Lightweight Hoody?

The Arc'teryx Kyanite is a lightweight, surprisingly warm jacket that offers much more mobility than other fleeces we tested. It is important to note that this is not a heavyweight fleece to wear as a standalone jacket in the winter. However, the slim fit makes it a great option for those who want a lightweight mid-layer to layer underneath a heavier fleece or a hardshell jacket. It's a great choice for long-distance through-hikers as well as more casual summer strolls.

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