Before floundering around in the rabbit hole of running rain gear, I had this delightfully naïve notion that a perfect rain jacket could exist. I’d routinely check in with fellow gear reviewers to see if they had captured the unicorn.
Surely somebody had fine-tuned the ratio of breathability to waterproofing in a way that could keep us all from sweltering while also protecting us from various degrees of precipitation.
Well, it turns out that there is no perfect jacket for all conditions. The best rain jacket for especially rainy climates is going to be different than the best rain jacket for more temperate areas. And the best rain jacket for those of us whose body temperatures run hot is going to be different than the best one for those who run cold. The good news is that there are many great options available, including the Rab Kinetic Ultra Waterproof Jacket.
Rab Kinetic Ultra Waterproof Jacket Fabric and Features
I have had the pleasure of testing the Rab Kinetic Ultra Waterproof Jacket. For what this jacket offers, the price point seems fair and middle-of-the-road. This piece is made with Proflex three-layer recycled polyester stretch knit fabric and a polyurethane membrane. The jacket weighs in at an advertised weight of 8.9 ounces (254 grams) for a women’s medium, and 9.7 ounces (277 grams) for a men’s medium.
Three-layer fabrics feature an external durable water repellant (DWR) treated outer shell, a waterproof material in the middle, and a thinner internal fabric. The primary purpose of the thin internal membrane is to protect the pores of the waterproof layer from getting clogged with sweat, dirt, or oils from our skin. The treated outer fabric keeps rain out and helps maintain optimal breathability.
Rain gear featuring 2.5-layer construction is similar, though the internal protection from grime may be merely painted on — hence its recognition as half a layer. A 2.5-layer jacket may be slightly lighter, but require more frequent cleaning and may not be as durable as the three-layer counterpart.
Keeping with the care instructions on the garment, I’ve tossed this jacket in the washing machine after most runs (tumble dry low is okay) and have not yet noticed any decline in performance.
While I’m notoriously a solid size medium (UK size 12) in most all women’s clothing, and other Rab items, the size small (UK size 10) I tested in this jacket fits remarkably well. I’m five feet, seven inches tall and about 135 pounds. It is form-fitting yet still has ample room for full range of motion.
The satisfyingly soft and stretchy result of these deeply thought-out layers is a simple jacket with the following details:
- One square zippered pocket on the left sleeve
- A close-fitting cap style hood that can be easily rolled up and stowed in the collar of the jacket
- Rear hood vent for airflow
- Two rear yolk ventilation holes for airflow; overlapping vents maintains protection from precipitation
- Extended cuffs with stretch binding to keep your hands protected and warm
Rab Kinetic Ultra Waterproof Jacket Waterproofing and Breathability
Waterproofing and breathability ratings are helpful to consider when deciding what the best rain jacket may be for you, given your running environment. Generally speaking, the higher the waterproof rating, the lower the breathability, and heavier the jacket.
Many trail runners wear jackets with a lower level of waterproofing and a higher level of breathability for a couple of reasons. First, this combination generally results in a lighter jacket. Second, you’re less likely to overheat while running if breathability is high and waterproofing is low, since that type of jacket allows your own moisture and heat to escape, while allowing a bit of moisture and cool air in.
Having also tested and reviewed the Rab Men’s Phantom Waterproof Pull-On here on iRunFar, I was surprised to see the Rab Kinetic Ultra Waterproof Jacket described as comparably less waterproof, as that was not my experience. The Phantom is an incredibly lightweight jacket that I would take to keep some cold wind and very light rain out. But, like most ultralight jackets, the Phantom will eventually tightly wrap to your arms if subjected to anything beyond light rain for an extended period of time.
The waterproofing in the Kinetic Ultra holds up considerably longer before wetting out. Before discussing waterproof ratings in further detail, I mention this comparison to illustrate how the rating system remains less than a perfect science, even within a single brand with different products.
The UTMB race requires runners to carry a hooded jacket with a minimum waterproof rating of 10,000 Schmerber units. The Schmerber unit is a measure of the impermeability of a textile, meaning how much wind or water can get through; this is measured in millimeters (mm), and the most impermeable jackets are rated up to 30,000 mm. Rab waterproof ratings are defined in terms of Hydrostatic Heads (HH), a measurement more commonly used in the United Kingdom, which directly correlates to Schmerber units.
Rated at 10,000 HH/mm, the Rab Kinetic Ultra Waterproof Jacket would meet the UTMB minimum specifications for waterproofing. Gore-Tex, by comparison, with the exception of the newer Gore-tex Infinium technology, is considered about 28,000 mm/HH.
Using the UTMB requirements as a gauge, I would agree that the Kinetic Ultra is a good example of a more minimalist jacket that I would feel comfortable taking into the mountains for extended days out. If worn on a cool, blustery, and drizzle-to-moderate precipitation day, this jacket performs flawlessly. However, if you find yourself in a more aggressive downpour, the jacket will wet through.
A past iRunFar review of the Ultimate Direction Ultra Jacket V2 paints an entertaining and relatable picture of circumstances that warrant higher range waterproofing. If you’re looking for a jacket that will protect you from potentially extreme elements, keep perusing. If your climate and internal thermostat resonate with mine, keep reading!
From a breathability standpoint, the Rab Kinetic Ultra Waterproof Jacket really shines.
First, let’s back up, a fabric’s breathability is called its moisture vapor transmission rate (MVTR) and it’s measured in grams per square meter per day (gm/m2/24hrs). With a moisture vapor transmission rate of 35,000 gm/m2/24hrs, this jacket is considered highly breathable.
If you’re familiar with the Rab Men’s Phantom Waterproof Pull-On, rated at 20,000 gm/m2/24hrs, or a similar jacket like Patagonia Houdini, you can expect more breathability from the Kinetic Ultra.
I tend to run relatively hot, so I have had a hard time running in less-breathable jackets without overheating when the temperature is warm enough to create rain versus snow. Protection from precipitation coming in doesn’t matter when you’ve sweat enough beneath a jacket to be equally saturated.
Even in a jacket as breathable as the Kinetic Ultra, I still struggle with heat while climbing a couple of thousand feet in the rain. When this is the case, I’ll usually tie it around my waist until I hit the top, and pop it on to keep me from getting too chilly on the descent and remainder of my run.
Rab Kinetic Ultra Waterproof Jacket Overall Impressions
In my climate in Oregon, if you have a jacket like the Rab Kinetic Ultra Waterproof Jacket with very good breathability and reasonably effective waterproofing, that is the perfect combination for the majority of wet-weather forecasts. If I were headed into more aggressive rain, especially for a long duration and/or at a higher altitude, I would certainly consider taking a more water-protective jacket.
One could argue that for moderate-range waterproofing, this jacket is heavy. While I often catch myself being stingy about hauling around more drinking water than I think I may need, I can’t say the jacket’s 8.9 ounces has been especially cumbersome or prevented me from wearing it or packing it along on day-to-day training runs.
My only other bit of constructive criticism would be that it could use another zippered pocket or two. At the risk of sounding greedy, how great would it be if even moderately waterproof jackets had fully waterproof pockets?
A forecast of rain can be so obscure. I’ll no doubt forever find it easier to dress for extreme temperatures compared to rain. Maybe a fancier weather app would help clear up some grey areas for me, but when the forecast calls for a 100% chance of rain, I still never really know what that means. Are we talking a 100% chance of a little bit of rain, or a 100% chance of hard rain?
The morning I had the privilege of testing how the Kinetic Ultra stood up to a full-on torrential downpour, I recall my friend yelling over the sounds of crashing thunder and deluge, “ANNIE, I THINK THIS IS 100%!” Past experience sweltering under less breathable jackets meant that deluge days were the only days I would grab rain gear.
As a product of waterproofing with superb breathability, wind protection, and stretch, the Rab Kinetic Ultra Waterproof Jacket is an easy choice that results in far less sweating and sees many more miles on the trail.
Call for Comments
- Have you tried the Rab Kinetic Ultra Waterproof Jacket yet? If so, what do you think?
- Do you use another rain jacket that provides you the right amount of waterproofing and breathability for your applications?
[Editor’s Note: If you’re affiliated (i.e., an employee, ambassador, etc.) with a shoe brand, please share your relation in each of your comments on this article. Thanks!]