Ultra-light and ultra-tough: Is this the ultimate waterproof shell for mountain runners?
Overview
The Inov-8 Stormshell is an elite-level waterproof running jacket crafted for trail runners, fell runners, and mountain athletes who demand total protection in the lightest form possible. At just 150–163g, it delivers 20,000 mm waterproofing, 20,000 g/m²/24hr breathability, and a packable profile small enough for vest pockets.
Whether you’re racing a sky marathon, running in the British fells, or prepping for mandatory kit checks, the Stormshell has become a go-to shell in extreme conditions.
Key Specifications
| Feature | Inov-8 Stormshell Jacket |
|---|---|
| Fabric | Pertex® Shield 2.5-layer |
| Waterproof Rating | 20,000 mm HH |
| Breathability (MVTR) | 20,000 g/m²/24hr |
| Weight | ~150–163g (size dependent) |
| Packability | Packs into own chest pocket |
| Hood | Adjustable with wired peak |
| Cuffs & Hem | Elasticated with thumb loops |
| Fit | Athletic cut for fast movement |
| Pocket(s) | 1 external zipped chest pocket |
| Price | £180 / $215 |
Materials & Design
At the heart of the Stormshell is Pertex® Shield, a 2.5-layer waterproof fabric known for balancing breathability and storm protection. Despite its featherweight build, it features:
- Fully taped seams
- A soft hand-feel that doesn’t crinkle excessively
- Durable PFC-free DWR finish
- Excellent sweat vapour transfer during high-output runs
The fabric’s 20K/20K rating ensures reliable weather protection without trapping moisture inside.
Fit & Comfort
The cut is streamlined but not restrictive—ideal for:
- Wearing over a short-sleeve or light long-sleeve
- Allowing full shoulder and arm articulation
- Keeping bulk low for race vest layering
Other comfort-focused details include:
- Elasticated cuffs with thumb loops to prevent sleeve ride-up
- Dropped rear hem to cover the lower back while running
- Pre-shaped elbows and articulated patterning for natural movement
The jacket is not designed for layering over bulky insulation—but that’s by design. It’s race kit, not basecamp gear.
Weather Resistance & Real-World Performance
Field-tested across multiple UK fell races and long training runs in Scottish downpours, the Stormshell handled:
Heavy Rain
- Kept water out for hours in steady rainfall
- No leakage at seams or zip—even in downpours
- Hood’s wired peak prevented water drip into eyes
Wind
- Effective wind blocker on exposed ridgelines
- Hood stays in place thanks to elastic adjuster + fit-hugging profile
- Sleeves and hem didn’t ride or balloon in gusts
Breathability
- Managed sweat well on sustained climbs and tempo runs
- Vapour transfer noticeable, especially with mesh-backed base layers
- Long zip and chest snap tab let you vent without the jacket flapping open
This shell doesn’t overheat easily, making it one of the more “keep-it-on” waterproofs for fast-paced runners.
Pocket & Packability
The external zipped chest pocket is functional—big enough for:
- A slim phone
- Gel, buff, or emergency cash
- Race map (tightly folded)
Bonus: the jacket packs into its own pocket, forming a compact bundle that fits easily into race vests or bumbags. It’s a gold standard for mandatory race kit compliance.
Safety Features
- Reflective logos on front and rear for low-light visibility
- Minimal branding keeps weight low and the look sleek
- Press stud tab at chest allows partial zip-open venting without flapping
Pros & Cons
Pros
- ✔️ Featherweight and highly packable
- ✔️ Excellent waterproof and breathability ratings
- ✔️ Race-ready athletic fit with motion-friendly features
- ✔️ Effective hood design with wired peak and adjusters
- ✔️ Meets most mandatory kit lists for mountain races
- ✔️ Packs into its own pocket
Cons
- ❌ Premium price tag
- ❌ Chest pocket is small for OS maps or gloves
- ❌ Too slim-fitting for bulky layering
- ❌ Not ideal for daily use or prolonged abrasion (e.g. scrambling)
Compared to Similar Running Shells
| Jacket | Inov-8 Stormshell | Montane Minimus Nano | Salomon Bonatti Trail |
|---|---|---|---|
| Weight | 150–163g | ~100g | ~210g |
| Waterproof Rating | 20,000 mm | 20,000 mm | 10,000 mm |
| Breathability (MVTR) | 20,000 | 20,000 | Moderate |
| Fit | Slim athletic | Race-cut pull-on | Relaxed athletic |
| Pocket Layout | 1 chest pocket | 1 chest (stow) | 1 rear zip |
| Price | ~£180 | ~£140 | ~£165 |
Verdict: The Stormshell hits the sweet spot between race-legal compliance, performance, and durability. Slightly heavier than the ultralight Minimus, but more robust and fully featured.
Final Thoughts
The Inov-8 Stormshell Jacket is a top-tier choice for trail runners, fell racers, and fastpackers who require dependable waterproof protection in the lightest package possible. It’s built for performance over polish, stripping away fluff while retaining every function that matters.
It’s not the most versatile waterproof for casual walking or travel, but for runners facing wind, rain, and big hills—it’s a game-changer. If you need a race-proven, pack-sized fortress, this is it.
