There is no single best trail jacket. It depends on the weather you face and the intensity of your effort. A start under clear skies can turn into a downpour on an exposed ridge within a few kilometres, and the chill after a long climb does not wait to be announced. Three families cover most outings: the waterproof jacket for rain and altitude, the windproof jacket for wind and short showers, and the warm mid-layer for dry cold. Choosing well means identifying your need.
This guide compares the Cimalp range by use. You will find the criteria that really matter: Schmerber waterproofness, breathability, weight and fit, a model-by-model selection, and a summary table for comparison. The aim is simple: find the jacket suited to your activity.
Contents
- Our recommendation at a glance
- The 3 families of trail jackets
- Waterproof jackets (hardshell)
- Windproof jackets
- Warm mid-layer jackets
- Our in-house technologies: Ultrashell and CimaWind
- Which jacket for the season and weather?
- UTMB mandatory kit
- Cimalp range comparison table
- What independent tests say
- FAQ
Our recommendation at a glance
Choose by condition first:
- Rain, altitude, ultra-distance races: a waterproof jacket with a membrane. Our most advanced model is the STORM PRO +, designed to be worn over a pack.
- Wind, brief showers, quick outings: a lightweight, packable windproof jacket such as the WIND or SKIN.
- Cold, dry conditions, winter, temperature control: a warm, breathable mid-layer such as the BLIZZARD fleece.
Most regular trail runners end up owning all three. They do not replace one another; they complement each other depending on the season and the race.
The 3 families of trail jackets: waterproof, windproof, mid-layer
A trail jacket serves a specific purpose. The three-layer system structures this choice. The base layer moves sweat away. The mid-layer provides warmth. The outer layer protects against rain and wind. A trail jacket is either an outer layer, waterproof or windproof, or a warm, breathable mid-layer.
Confusing these functions leads to two classic mistakes. Taking a windproof jacket into driving rain lets water through after an hour. Conversely, taking a thick hardshell on a cool, dry outing makes you sweat and leaves you cold when you stop. The right approach is to identify the main constraint—rain, wind or cold—then choose the corresponding family. The three can be combined: a windproof or waterproof jacket over a mid-layer when conditions worsen.
#1 Waterproof jackets (hardshell)
A waterproof trail jacket protects against durable rain thanks to a membrane and taped seams. It is the essential safety layer for long, exposed outings. It is assessed using two figures: waterproofness, measured in Schmerber, and breathability, expressed in g/m²/24h.
What Schmerber rating should you aim for?
Schmerber measures the water column a fabric withstands before allowing moisture through. The higher the figure, the longer the protection lasts.
| Level | Use |
|---|---|
| 10,000 Schmerber |
Waterproof, including in heavy rain. It shows its limits mainly over several hours or in very heavy rain. Minimum required by UTMB regulations. |
| 20,000 Schmerber |
A full day in the rain. Recommended level for regular trail runners. |
| 30,000 Schmerber and above |
Extreme conditions, prolonged rain, high exposure. |
Breathability matters just as much. A highly waterproof but poorly breathable jacket leaves you soaked from the inside on climbs. Choose a fabric that moves vapour away during exertion to avoid condensation. Two other criteria matter when choosing. Weight determines how much space the jacket takes up in your pack when not worn. The fit must allow it to be worn over a pack, with enough length in the back and sleeves that cover the wrist in action.
Cimalp waterproof selection
The STORM PRO + is our most advanced waterproof jacket. It uses the 3-layer Ultrashell membrane and delivers 20,000 Schmerber waterproofness and 80,000 g/m²/24h breathability. This level of breathability places it among the most breathable jackets in its segment. Its zips are water-repellent YKK Aquaguard zips and its hood is fitted with a rigid peak. Above all, it is designed to be worn over a trail pack, while retaining access to soft flasks and pockets. It is available for men and women.
20,000 Schmerber: twice the UTMB regulatory minimum (10,000), for 65 g more than the STORM (225 g versus 290 g for the STORM PRO). Source: cimalp.com product pages.
The STORM PRO (290 g) uses the 3-layer Ultrashell membrane, with the same 20,000 Schmerber and 80,000 g/m²/24h as the STORM PRO +, in a classic trail fit.
The STORM (225 g) uses Ultrashell Slim 2.5-layer fabric rated at 10,000 Schmerber. This lighter level of protection still meets the regulations for ultra-distance races. Women’s and men’s versions each have a dedicated fit; find the women’s models in our women’s running jackets. To explore the full range, see our waterproof trail jackets.
One point often overlooked: getting to your gear in the rain. We cover it in detail in our article trail running in the rain.
#2 Windproof jackets
A windproof jacket protects against wind and short showers, without the full barrier of a waterproof membrane. It is lighter, more breathable and packs into a pocket or pack. It is the outer layer for quick outings and changeable but not truly rainy conditions.
The difference from a waterproof jacket lies in duration. A water-repellent windproof jacket beads water and fends off a shower. In sustained, prolonged rain, it will eventually let water through. In return, it breathes better and weighs less. For a fast trail runner who prioritises lightness, it is often the most-worn jacket of the year.
Do not confuse them: a windproof jacket repels a shower, but lets water through in sustained, prolonged rain. On a long outing in uncertain conditions, a waterproof jacket remains the safe choice.
Packability is decisive here. A good windproof jacket folds into its own pocket and fits in your hand or a pack pocket. Take it out when the wind picks up on a ridge, stow it as soon as it warms up. It is the ideal compromise for spring and autumn, and for outings with uncertain weather.
115 to 140 g for a windproof jacket, compared with 225 to 296 g for a waterproof jacket — up to twice as light, at the expense of protection in sustained rain. Source: cimalp.com product pages.
At Cimalp, the WIND (140 g) uses stretch CimaWind fabric, a water-repellent DWR treatment and wind resistance up to 60 to 90 km/h.
The SKIN (115 g) takes the ultra-light approach further: once packed down, including the hood, it fits in your hand. A windproof gilet completes the range to protect the torso without restricting the arms.
#3 Warm mid-layer jackets
The mid-layer provides warmth. In trail, it takes the form of a technical, breathable, stretchy fleece worn over the base layer and, if needed, under an outer jacket. Its role is not to protect against rain, but to retain body heat in cold, dry weather while moving sweat away.
It is mainly used in winter, at altitude, or on long outings alternating between effort and breaks. A good thermal trail jacket stays lightweight, avoids retaining moisture, and combines with a windproof or waterproof jacket when the weather deteriorates.
The BLIZZARD (370 g) is our warm mid-layer for trail, warm and stretchy, close-fitting enough to wear on its own or under an outer layer.
Our in-house technologies: Ultrashell and CimaWind
Cimalp develops its own membranes rather than using generic solutions. Two technologies structure the trail range.
Ultrashell is our waterproof-breathable membrane. On the STORM PRO +, it uses a 3-layer construction: an outer fabric, the membrane, and a lining that protects the membrane and improves comfort. This construction aims to balance durable waterproofing with moisture vapour transfer during exertion.
CimaWind is our windproof fabric, used on the SKIN and WIND models. It blocks wind while remaining highly breathable, for outings where protection is needed without overheating. Choosing a range therefore depends as much on the technology as on the waterproofness rating.
Which jacket for the season and weather?
The right model changes with the season. Here is a quick guide by condition.
| Conditions | Recommended jacket | Cimalp model |
|---|---|---|
| Heavy rain, ultra, altitude | Waterproof | STORM PRO + |
| Wind, short showers, quick outings | Windproof jacket | WIND, SKIN |
| Dry cold, winter | Warm mid-layer | BLIZZARD |
| Combined cold and rain | Mid-layer + waterproof jacket | BLIZZARD under STORM PRO + |
In winter, the layering principle comes first. Layers are added according to effort and exposure, with the windproof or waterproof jacket stowed in the pack while conditions allow.
For ultra events and racing: mandatory UTMB kit
In UTMB circuit races, a hooded waterproof jacket is part of the mandatory kit. Its absence, or a non-compliant jacket, results in immediate disqualification, just like forgetting a headlamp or survival blanket. The jacket must have a hood and a waterproof membrane rated at least 10,000 Schmerber, with taped seams. A 20,000 Schmerber rating and good breathability are recommended.
The STORM PRO + delivers 20,000 Schmerber, twice the required minimum, and a hood with a rigid peak. The STORM, approved for ultra events, reaches the regulatory threshold of 10,000 Schmerber at a low weight of 225 g. Always check your race regulations before the start, as each event may specify its own requirements.
Avoid — a jacket below 10,000 Schmerber for a race where this is required by the regulations.
Best for — 20,000 Schmerber (STORM PRO or STORM PRO +) as soon as the race is long or the weather is uncertain; 10,000 Schmerber (STORM) is sufficient for training.
Official sources: UTMB Mont-Blanc mandatory kit and 2026 regulations.
Cimalp range comparison table
| Model | Family | Use | Technology | Waterproofness | Weight (M) |
|---|---|---|---|---|---|
| STORM PRO + | Waterproof | Ultra, worn over pack | Ultrashell 3-layer | 20,000 Schmerber | 296 g (M) |
| STORM PRO 4 H | Waterproof | Rain, versatile trail | Ultrashell 3-layer | 20,000 Schmerber | 290 g |
| STORM 4 H | Lightweight waterproof jacket | Ultra-light, performance | Ultrashell Slim 2.5-layer | 10,000 Schmerber | 225 g |
| WIND | Windproof jacket | Wind, short showers | CimaWind (water-repellent DWR) | Not waterproof | 140 g |
| SKIN | Ultra-light windproof jacket | Quick outings, wind | CimaWind (water-repellent DWR) | Not waterproof | 115 g |
| BLIZZARD | Warm mid-layer | Dry cold, winter | CIMATHERM® | Not applicable | 370 g |
What independent tests say
The STORM PRO has been tested by specialist publications with no declared commercial ties to Cimalp. Running-Addict.fr, which states that it has “no affiliate relationship or other payment” for covering Cimalp products, tested it in temperatures of −10 to −20 °C in Quebec and rates its quality on a par with the Salomon Bonatti. Advnture.com confirms the same technical construction (Ultrashell, 20,000 mm, 80,000 g/m²/24h) in a jacket weighing 290 g and describes it as versatile and reliable.
FAQ
Waterproof, windproof or mid-layer: which should you choose?
Identify your main constraint. Durable rain: waterproof. Wind and short showers: windproof. Dry cold: warm mid-layer. All three can be combined when conditions worsen.
What Schmerber rating should you aim for in trail?
10,000 Schmerber is enough for light rain and meets the UTMB minimum. 20,000 Schmerber covers a full day in the rain.
Which trail jacket for winter?
In winter, combine a breathable warm mid-layer with an outer layer suited to the weather. In dry cold, a thermal jacket is often enough. In rain or snow, add a waterproof jacket over the top.
What is a mid-layer in trail?
It is the mid-layer that retains body heat while moving sweat away. It is worn over the base layer and, if needed, under a windproof or waterproof jacket.
Which jacket meets UTMB mandatory kit requirements?
A hooded waterproof jacket, a membrane rated at least 10,000 Schmerber and taped seams. A 20,000 Schmerber rating is recommended. Always check your race regulations on the official UTMB website.
Which waterproof trail jacket for women?
The STORM range is available in dedicated women's fits, including the STORM PRO +. The selection criteria remain the same: waterproofness, breathability and a fit suited to wearing a pack.
What is the difference between the STORM PRO and the STORM PRO +?
Both share the same 3-layer Ultrashell membrane, 20,000 Schmerber and 80,000 g/m²/24h. The STORM PRO + adds a back gusset, front gussets and side zips so it can be worn over a pack or trail vest without losing access to flasks and pockets.
How do you pack your trail jacket in your bag?
Fold it onto itself by rolling it up to reduce its volume, then place it in an easily accessible pocket of your pack or vest: you need to be able to take it out quickly when the weather changes, without unpacking everything else.
Key takeaways
- Three families of trail jackets meet three different constraints: durable rain (waterproof), wind and short showers (windproof), dry cold (warm mid-layer).
- Schmerber measures rain resistance: 10,000 is the UTMB regulatory minimum, while 20,000 provides protection for a full day in the rain.
- The STORM PRO + remains the only one designed to be worn over a trail pack without losing access to it.
- Independently tested by Running-Addict.fr and Advnture.com, the STORM PRO confirms Cimalp's claimed specifications in the field.
Photo credits: Cyrille Quintard (outdoor photos)
