On made its name with running shoes before building a serious apparel line. The Weather Jacket is its answer to changeable conditions, from wind and drizzle to deep cold, and it takes a clear stance: stay light and breathable rather than chase full waterproofing. RunMorph cross-checked independent reviews to pin down exactly what this jacket protects you from, and what it doesn't.
© On, official photo used for editorial purposes
The On Weather Jacket is a windproof, water-repellent running jacket built to stay on for the whole run, thanks to large venting panels that dump heat without letting the wind in. It's deliberately not guaranteed waterproof: the brand positions it as "weatherproof" rather than "waterproof," with seams left untaped in some zones and a forearm ventilation mesh that's more exposed to moisture. Light, close-fitting and packable into its own chest pocket, it targets windy runs and drizzle rather than sustained downpours.
In a decade, On has become one of the fastest-growing running brands, powered by its CloudTec soles. The Weather Jacket extends that success into apparel: a jacket the brand pitches as the ideal companion "when your run goes sideways," designed to stay on your back the whole time rather than come on and off with every passing shower.
It joins an apparel lineup RunMorph already covers widely, alongside the Race Singlet 2 on the technical top side, and it goes up against more traditional rain jackets such as the Salomon Bonatti Trail, guaranteed waterproof to 20,000 Schmerber. The difference in philosophy is clear from the product page: the brand never calls the Weather Jacket "waterproof," only "weatherproof." That nuance changes everything if you're counting on it in heavy rain.
RunMorph's advice: if you're training for an ultra or a race whose rules require a waterproof jacket with sealed seams, check the spec sheet carefully before you buy the Weather Jacket. It isn't designed to tick that box.
| Brand | On |
| Model | Weather Jacket |
| Type | Windproof, water-repellent jacket, weatherproof (not guaranteed waterproof) |
| Treatment | DWR (durable water repellent) on the main polyamide ripstop fabric |
| Ventilation | Flap-covered panels on the chest and shoulders, stretch mesh on the forearms |
| Seams | Taped on the main body, mesh zones unsealed |
| Hood | Integrated, rear adjustment cord, stiffened peak |
| Storage | Water-repellent zippered chest pocket that doubles as a stuff pocket (packable) |
| Visibility | Reflective details |
| Official price | €240 MSRP, commonly found between €170 and €180 on sale |
© On, official photo used for editorial purposes
RunMorph cross-checked two in-depth English-language reviews, each run over several weeks of fall and winter outings, to hold the claimed specs up against real-world use.
On wind protection and breathability, both reviews agree completely: the wide ventilation flaps, open at the bottom and closed on top, let hot air escape without letting wind or head-on rain in. Both describe this system as the jacket's real technical achievement. One tester says he finally found a running jacket he keeps on for the whole run instead of peeling it off after ten minutes and tying it around his waist, on short runs on the flat and big mountain days alike. The close fit and very thin ripstop fabric also earn praise for their lightness and for staying out of the way of your stride.
On waterproofing, though, both reviews add a major caveat that RunMorph wants to pass on clearly. The water-repellent treatment handles light rain and short showers well, but one review states explicitly that this is not a waterproof jacket in the strict sense. The brand itself labels it "weatherproof" rather than "waterproof," wording usually reserved for jackets that can't claim full waterproofing. Two culprits: seams aren't sealed across the whole jacket (a prerequisite for most mountain races that require a waterproof jacket), and the unprotected mesh inside the forearms is flagged as a likely entry point for moisture in sustained rain.
| On Weather Jacket | Salomon Bonatti Trail | |
|---|---|---|
| Waterproofing | Weatherproof, not guaranteed waterproof | 20,000 Schmerber, guaranteed waterproof |
| Seams | Taped, mesh unsealed | Fully sealed |
| Breathability | Excellent, wide ventilation flaps | Good but more closed |
| Weight | Very light | 195 g |
| Use | Wind, drizzle, comfortable long runs | Races that require a waterproof jacket |
| Price | ~€240 (often €170-180) | Varies by retailer |
The two jackets look alike but target different uses. The Weather Jacket goes all in on breathable comfort and the fact that you can keep it on the whole time, even if that means giving up a full waterproofing the brand never claimed. The Bonatti Trail ticks the guaranteed-waterproof box with its 20,000 Schmerber rating and sealed seams, a prerequisite for regulated mountain races. If your playground is mostly wind and drizzle in training, the Weather Jacket wins on comfort. If you're preparing for a race that requires a certified waterproof jacket, the Bonatti Trail remains the safe choice.
The Weather Jacket delivers on its promise of breathable, all-run comfort, a real asset on windy runs and in drizzle. But it doesn't replace a certified waterproof jacket if your goal is a race that requires one, or if you regularly run through heavy downpours.
The On Weather Jacket pulls off a real feat on breathability and all-run comfort, with a ventilation system that lives up to its promises in independent testing. It openly accepts that it isn't a waterproof jacket in the strict sense, and the brand says so clearly itself. 7.9/10: an excellent, comfortable windproof jacket, not to be confused with a technical rain shell for regulated racing.