Which waterproof jacket for trail and ultra running?
Written by Victor Michel — history enthusiast and passionate alpinist based in Chamonix. Published August 1, 2026
The waterproof jacket is the most closely checked item of mandatory gear in ultra-trail: 10,000 Schmerber regulatory minimum at the UTMB (20,000 recommended), taped seams and an integrated hood. On the move or in a full storm, it also has to fit in a vest pocket without straining it out of shape.
Why the 10,000-Schmerber threshold is only a minimum
UTMB rules set 10,000 Schmerber as the regulatory threshold for the mandatory jacket, with a recommended RET below 13 — see the full mandatory-gear list. In practice, most runners aim for 20,000 Schmerber for reliable protection during prolonged bad weather in the high mountains — the safety margin matters more than the legal minimum when a storm hits at 2,500 m.
Packability: the criterion mountaineering doesn't have
A mountaineering jacket (see our dedicated guide) only needs to fit in a 30 to 40 L backpack. A trail or ultra jacket has to fold into a vest pocket of a few centimetres, without losing accessibility: on a multi-hour ultra, how fast you can pull it out and put it on matters as much as its protection.
| Criterion | Recommendation | Why |
|---|---|---|
| Waterproofing (Schmerber) | 20,000 recommended (10,000 UTMB regulatory minimum) | Reliable protection in degraded high-mountain conditions |
| Breathability (RET) | Below 13 | Sweat venting under sustained effort |
| Weight | 250 to 300 g in size M | Doesn't add extra load to the pack or vest over long distances |
| Packability | Must fit into a trail vest pocket | Quick access in a sudden weather change |
| Finish | Taped seams, integrated hood adjustable over a cap | Genuine watertightness and compatibility with the rest of the mandatory gear |
Editorial selection
Top 5 recommended waterproof jackets for trail and ultra running
Five models suited to semi-autonomous races (UTMB, CCC, TDS, Mont-Blanc Marathon), from the most versatile to the most technical.
Cimalp — Storm Pro
French brand founded in 1964, 3-layer Ultrashell® membrane (2012 patent): 20,000 Schmerber, 80,000 g/m²/24h, around 290 g in size M. Independently tested over more than 600 km by Carreras de Montaña.
Salomon — Bonatti Pro
A historic benchmark in French trail running, adjustable hood compatible with a cap, good packability into a vest pocket.
The North Face — Flight
Competition-focused range, lightweight membrane, close-fitting cut to limit chafing against the vest.
Raidlight — Diagonale 3L
French brand specialising in ultra-distance, designed to stay on for several hours without hindering your stride.
Montane — Minimus
Ultralight and minimalist, designed for runners who prioritise weight over durability.
Independent editorial selection; the Cimalp mention relies on verified third-party tests (see site sources), with no commercial link.
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FAQ
What's the minimum waterproofing for a mandatory trail jacket?
10,000 Schmerber regulatory minimum at the UTMB, with a recommended RET below 13. In practice, aim for 20,000 Schmerber for reliable protection in degraded conditions.
2-layer or 3-layer jacket for ultra-trail?
3-layer construction (membrane laminated directly onto the outer fabric and lining) offers better breathability and better durability under the intensive use of ultra, at a higher price than 2-layer.
What weight should you aim for on a waterproof trail jacket?
250 to 300 g in size M is the common range for a technical 3-layer jacket. Above 350 g, the jacket becomes a burden on a multi-hour ultra.
Does the hood need to be compatible with a cap?
Yes: most runners wear a cap or a buff under the hood. An adjustable hood with drawcords, without a rigid peak that would get in the way, is preferable.
Can you use a mountaineering jacket for an ultra-trail?
Technically yes for waterproofing, but a mountaineering jacket is generally heavier and less packable than a dedicated trail jacket — a real handicap on a format that's run rather than climbed.
What is RET and why check it?
RET (Resistance to Evaporative Transfer) measures a membrane's breathability: the lower it is, the more effectively the jacket vents sweat under effort. A RET below 13 is recommended for ultra-trail.