The Rab Borealis is the lightest weight offering from this UK-based apparel brand, and it is an excellent layer for active pursuits. This thin jacket provides limited protection from weather, and while it has a DWR treatment for unexpected wet conditions, it is much better suited for breezy weather encountered while climbing, hiking or biking. The Borealis offers above-average breathability and mobility, while also giving great durability while working your way up a difficult climbing route.
Rab Borealis Review
Compare prices at 2 resellers Pros: Incredibly light, very mobile
Cons: Limited weather protection, few features
Compare to Similar Products
Our Analysis and Test Results
Rab utilizes an unlined, single weave Lightweight Matrix fabric as the body of the Borealis. This is further treated with a DWR to give it some additional protection from moisture. While it shed light precipitation for a couple of minutes, wet weather really is not its strong suit. In comparison to other lightweight models, it certainly did not hold up as well in the shower test. Where it did much better was in windy weather.
The Borealis does have a hood; it has a lycra binding to keep it secure around a hat brim or a hood, but does not have any other closures. Its trim fit stayed in place around our waist, and cinches on either side can further tighten the hem, but it does not have the longer hem that would make it more useful in winter weather.
Breathability was something that this jacket has under control. We hiked, biked, and climbed our way through the mountains as well as on our local trails, and this thing can wick moisture as well as a running top. Even when we layered a slightly thicker fleece base layer underneath on cooler climbs, we did not notice a dramatic decrease in breathability, due to the lack of any lining or fleece backing. As only a single, thin layer of stretchy fabric, there is little to keep heat trapped in., but the two large chest pockets are backed only by mesh, so if you are overheating, it is easy to open up your pockets (assuming your phone and lunch money are safe somewhere else) and dump all that excess warmth.
The mobility offered up by the Rab Borealis is excellent. The Lightweight Matrix fabric is undeniably stretchy, allowing for unrestricted range of motion. We have no problem feeling constricted when stretching tall for hard to reach holds at the crag, and certainly do not feel held back when sprinting uphill on a trail run. The fit is very trim, with little opportunity to layer much besides a light fleece underneath. The cut of the arms feel spot on, and do not fall down when we reach high above our heads, though those with longer arms may wish to size up. Similarly, the hem is cut rather high and might be difficult to fit well for a longer torso. Where we do feel uncomfortable is when wearing a helmet, the tight-fitting hood makes it hard to pull over a climbing helmet and move around.
This jacket weighs next to nothing, coming in at an astonishing .65 lbs. It is hard to even notice when you are wearing it, and it certainly does not take up much space in the pack when you don't need it, packing down to about the size of a softball.
We have less to report on the Borealis' features, as there aren't many. With such a lightweight layer, Rab got rid of some heavier features like a three-way hood closure, wrist closures or multiple pockets, instead going with a Spartan look; two pockets, a hood and a cinch around the hem, no more, no less. The quality YKK zipper is, like all of Rab's jackets, left-handed.
This slim-fitting jacket has a nice clean look, but it is not easy to mistake the wearer as an outdoor enthusiast. It looks good with a pair of jeans but does not have nearly the same cross-over appeal as other jackets. This is meant for moving fast in the mountains, and it is available in three bright colors (as well as the muted steel color shown here).
The Rab Borealis is quite a good deal. It falls just short of the Best Buy Award due to fewer available features, but with a nice trim fit and a much lighter weight, it should be considered the runner-up as a super mobile and breathable jacket at a very reasonable price.
If you find yourself up on a windy ridge or cliff wishing you had some extra protection at a very light weight, then the Rab Borealis is the jacket for you. Designed as a wind layer for climbers and other mountain athletes, this jacket stretches and breathes without holding you back.
— Ryan Huetter