The Arc'teryx Kyanite inhabits the lightweight fleece niche along with the Outdoor Research Transition Hoody, the Black Diamond CoEfficeint Hoody, and the Patagonia R1 Hoody. It's one of the warmer entries in the lightweight category but loses points for breathability and comfort.
While soft and stretchy, we wish this jacket had a longer hemline
While it's no R1, Arc'teryx aficionados will be happy with this lightweight fleece.
This jacket gets it's warming powers from the Polartec Power Stretch Pro fleece that comprises the entirety of the jacket. The slim fit of the Kyanite butts soft fleece right up against your skin, making it a thermally efficient mid layer. The hood is form fitting and designed to fit under a helmet and zips up to sit comfortably just above the chin. It's not as warm as the R1 hoody, but it insulates a little better than the super breathable Outdoor Research Transition Hoody, as well as the BD CoEfficient. If you're looking to turn the heat up just a little, the REI Co-Op Flowcore is a loftier, cozier entry that doesn't weigh much more than the Kyanite. For maximum warmth (at the expense of breathability) there's the heavy, weather-resistant The North Face Denali 2.
This fleece features a soft, form fitting scuba style hood.
Several features make this jacket a comfortable piece for layering. The elastic cuffs are perfect, tight enough that they stay in place when our testers put another layer on, but not so tight we couldn't comfortably pull up the sleeves. The handwarmer pockets are large and located high on the jacket, so they don't become inaccessible underneath a harness. Our one complaint about the Kyanite when it comes to comfort is that the hem is cut short when compared to the R1 or the Black Diamond CoEfficient Hoody. These longer jackets provide more coverage for warmth and don't ride up over a climbing harness, making difficult to grab gear on the fly.
The best breathers among the fleeces have a waffle-like grid pattern, allowing air and moisture to move out through the little channels in the grid. Constructed with a uniform piece of fleece, the Kyanite has no breathable channels. Light and thin, this jacket breathes much better than heavier fleece like the REI Co-Op Hyperaxis or The North Face Denali 2, but not as well as Jackets designed with better breathability in mind, like the Patagonia R1 Hoody.
This jacket layers easily under a light wind jacket.
As mentioned earlier, the Kyanite is an excellent mid-layer. We often wore it between a t-shirt and an insulated jacket. While it doesn't have thumb loops, the elastic cuffs are tight enough that they don't ride up your arms when putting them through the sleeves of another jacket. This Jacket has a slim, athletic cut, so it doesn't bunch up and feel uncomfortable under other layers.
The Kyanite doesn't fare well when exposed to the elements. The wind cut right through to our tester during his bike commutes. There is no DWR treatment on this fleece like the R1 Techface Hoody, so water soaks through almost immediately, but underneath a wind or waterproof layer, the Kyanite offers a thin layer of cozy insulation, and it feels great against the skin, especially compared to a nylon rain jacket.
The Kyanite falls into the midweight fleece category tipping the scales at 13.4oz. Perfectly packable for the backcountry. However, our testers feel the lighter weight Patagonia R1 Hoody is warmer.
Soft fleece dries quickly, but can't repel even light precip.
This jacket is fully equipped for all mountain adventures but looks fairly simple and low key, and our testers had no problem sporting it around town or around the house. It's available in five colors; Triton, Woad, Rooibos, Black, and Nighthawk.
If you want that dinosaur skeleton logo on your clothes, you gonna have to pay up. This fleece will set you back $179, but you'll get a good mid layer with the quality we've come to expect from Arc'teryx.
Small, soft zipper pulls reduce bulk and are better for layering.
This fleece inhabits the role of the traditional mid layer. While there aren't many bells and whistles, it's comfortable, it layers well, and it breathes much better than most insulated jackets, except for active insulation layers like the Patagonia Nano-Air Light Hybrid Hoody.
The Arc'teryx Kyanite scores middle of the road in all our metrics. It's a well-made jacket, but it lacks the never-take-it-off-even-to-sleep comfort of the Patagonia R1 Hoody, which remains the king of the breathable mid-layers.