When trail running, a jacket becomes a crucial piece of kit as soon as the weather turns, the wind picks up or the rain sets in. It must protect against moisture and wind, remain breathable during exertion, feature a cut that moves naturally with your stride, and pack down easily into a backpack or running vest. On exposed routes or in wet conditions, the right model helps you stay sheltered from the wind and dry, while also regulating body temperature so you can keep running comfortably. We’ve created this guide to help you choose based on the criteria that really matter: waterproofness, breathability, fit, weight, packability, hood design, pockets, and suitability for the season or distance.
Primary insights
- A trail running jacket is a technical garment: waterproof, windproof, breathable, and packable.
- Choose a fit tailored to men or women for optimum comfort and freedom of movement.
- The jacket should provide reliable protection against rain, wind, and snow, with fully taped seams.
- It’s essential to check the Schmerber rating and opt for high MVTR / low RET breathability values.
- A quality jacket should remain lightweight and compressible, featuring practical and secure pockets.
- Ventilation systems (zips, mesh panels) help regulate body temperature during exertion.
- For winter conditions, an insulated jacket with Primaloft fill retains warmth while staying breathable.
- For ultra-trail events, a 20,000 Schmerber jacket with a hood and fully sealed seams is often mandatory.
- Gore-Tex (waterproofing) and Primaloft (insulation) technologies deliver high performance and comfort.
- Maintain your jacket with a gentle wash and regular reproofing treatment.
Understanding the Specifications of a Trail Running Jacket
Differences between trail running jackets and sports jackets
The trail running jacket stands apart from standard running or other sports jackets thanks to its design specifically engineered for this discipline. Built to handle varied terrain, from steep climbs to fast descents, it must also cope with unpredictable weather conditions. It thus needs to provide superior protection. Trail jackets incorporate advanced technologies that enhance waterproofness and breathability while ensuring effective wind resistance. They are designed to be lightweight and packable, allowing runners to carry them easily. Unlike conventional running jackets, known for their lightness and generally intended for use in milder conditions, trail jackets feature waterproof-breathable membranes and closure systems that minimise moisture ingress while promoting sweat evaporation. They deliver genuine comfort throughout time spent outdoors. They may also include a hood, elasticated cuffs, and reinforced seams, all suited to the demanding nature of the sport.
Trail running jackets for men and women
In the trail running world, jackets are carefully tailored to accommodate anatomical differences between men and women, which directly affects the cut of each model. Men’s jackets are often designed with broader shoulders and a straighter fit, whereas women’s versions typically offer a more contoured silhouette. This distinction is crucial as it influences comfort and freedom of movement while running. Furthermore, depending on the model, some brands adjust the placement and size of pockets, as well as the design of zips, to ensure easy access and reduce discomfort during exertion. The fabrics selected are also chosen to deliver optimal flexibility and effective body temperature regulation, ensuring that both male and female trail runners find a jacket perfectly suited to their physique.
Selection Criteria for Your Trail Jacket
Protection against moisture and wind
The ability of a trail running jacket to withstand moisture, wind, and occasionally snow is essential for any endurance runner. Waterproofness and breathability are the cornerstones of this protection. Jackets designed for severe weather conditions must provide reliable defence against wet conditions while maintaining good surface water repellence and promoting moisture wicking to prevent overheating and internal condensation.
Membranes such as Gore-Tex enhance protection against both rain and wind. Depending on the model, they may feature waterproof zips and fully taped seams to improve weather resistance. Practical adjustments such as adjustable hoods and elasticated cuffs also help optimise protection and comfort in a variety of weather conditions.
Comfort and freedom of movement
A trail running jacket must deliver full range of motion, essential for tackling technical terrain. The fit should be close enough to reduce wind resistance, yet allow sufficient freedom around the shoulders, arms, and torso while running. Ergonomic hoods are equally important: they should stay securely in place during movement, adjust easily even when wearing a beanie, and stow away neatly without adding unnecessary bulk.
Ventilation systems
Body temperature regulation is crucial during long-distance runs. Passive ventilation systems, such as mesh panels integrated into key areas, play a vital role in enhancing the jacket’s breathability. These zones enable the continuous release of warm, humid air while allowing cool air to circulate, promoting natural cooling and greater comfort during exertion.
On certain models, this ventilation can be complemented and fine-tuned through strategically placed zips, such as under the arms or along the sides. By adjusting these openings, runners can better manage heat build-up and maintain comfort throughout their effort, without needing to stop and remove layers.
Weight and packability
The weight of the jacket is a critical factor when selecting trail running gear: an overly heavy jacket can tire the runner and negatively affect performance. Thanks to advances in modern materials, it is now possible to design jackets that combine lightweight construction with durability. These jackets not only offer effective protection against the elements but are also engineered to be highly packable, taking up minimal space in a trail running pack. This compactness ensures the jacket can be carried effortlessly, remaining unobtrusive and ready for use only when needed.
Storage options (pockets)
The pockets of a trail running jacket should be designed for easy and secure access, allowing runners to quickly reach their nutrition, phone, or keys. Depending on the model, some compartments provide enhanced protection against moisture, helping to keep contents dry when the weather deteriorates.
Safety (reflective details)
Visibility is a key safety factor, especially for runners training early in the morning or late in the evening. Well-positioned reflective elements on the jacket improve the runner’s visibility, making them more noticeable to other road or trail users in low-light conditions.
Waterproof, Breathable, and Windproof Jackets: Stay Dry in Any Weather!
Waterproof Rating: Understanding the Schmerber Rating
The Schmerber rating, named after Charles-Édouard Schmerber, is a measurement used to assess a fabric’s resistance to water penetration. Expressed in millimetres, it represents the height of a water column that the material can withstand during a hydrostatic pressure test before water begins to seep through the fabric. It is therefore a useful indicator for comparing materials under laboratory conditions, but it is not sufficient on its own to determine the overall performance of a jacket in real-world use.
For example, a rating of 10,000 mm means that the fabric can resist the pressure of a 10,000 mm water column. This level already provides solid protection for trail running in steady rain, provided that the jacket’s construction is consistent, with fully taped seams and water-resistant zips.
For very wet conditions or extended outings in the rain, jackets rated at 20,000 mm or higher can offer an additional margin of protection. However, the Schmerber index should be interpreted with perspective: more than the number alone, it is the combination of fabric, membrane, seam sealing, and build quality that determines the actual level of waterproof performance experienced in the field.
Breathability: Understanding MVTR and RET
The breathability of a fabric is crucial for sports apparel, as it refers to its ability to allow moisture vapour to escape during intense physical activity. This helps to reduce the build-up of humidity inside the jacket. Breathability is primarily assessed in two ways:
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MVTR (Moisture Vapour Transmission Rate): this measurement indicates the amount of water vapour a fabric can transfer over a 24-hour period, expressed in grams per square metre (g/m²/24h). The higher the MVTR, the more breathable the fabric. As a guideline, an MVTR of 30,000 g/m²/24h represents a very high level of breathability, while an MVTR of 5,000 g/m²/24h indicates more limited moisture transfer. It is important to note that MVTR values can vary depending on the testing methods used, so comparisons between brands should be made with caution.
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RET (Resistance to Evaporative Transfer): this index measures the resistance a fabric offers to the passage of water vapour. The lower the RET, the more breathable the garment. A RET below 6 corresponds to extremely high breathability. Values between 6 and 13 indicate good breathability, while a RET between 13 and 20 reflects moderate breathability that may feel more limited during intense activity.
Understanding these measurements helps trail runners choose a jacket suited to their needs. The goal is not to prevent perspiration, but to enable efficient moisture vapour transfer to maintain a more stable level of comfort during exertion.
How to Know If Your Jacket Is Waterproof?
Tags and Product Specifications:
The first thing to check is the jacket's labels. Manufacturers often indicate the fabric's waterproof rating, measured in millimetres (mm) using the Schmerber rating previously discussed. A rating of 10,000 mm or more is generally considered good for most weather conditions.
Materials:
Waterproof jackets are often made of materials like Gore-Tex, nylon, or polyester treated with hydrophobic coatings. These materials prevent water from penetrating while allowing sweat to escape.
Seam Design:
Check if the jacket has sealed seams. In a quality waterproof jacket, all the seams where fabric pieces are stitched together are sealed from the inside with waterproof tape. This prevents water from seeping through the needle holes left by stitching.
Water Spray Test:
If you want to test the waterproofness of a jacket you already own, you can perform a simple spray test. Hang the jacket and spray it with water. Observe if the water drips on the surface and runs off, or if it starts to soak into the fabric. If the water beads up, the jacket is still waterproof.
Checking Zippers and Flaps:
Waterproof jackets often feature waterproof zippers or flaps that cover the zippers to prevent water ingress.
Field Test:
For a more rigorous test, simply wear the jacket in the rain or during an activity where you are exposed to water. Check after a while if the inside of the jacket remains dry. If water does not penetrate, the jacket is effective.
Choosing According to the Type of Outing and Seasonality
Short Trail Runs vs Ultra-Races
The duration and intensity of a trail run directly influence the choice of jacket. For short-distance trail runs, a lightweight and packable jacket may be sufficient, provided it offers reliable protection against wind and moisture while remaining breathable. Conversely, for ultra-events, which demand longer exposure to often highly changeable mountain weather, it is advisable to opt for a more protective jacket. This should provide serious waterproofness, fully taped seams, breathability suited to sustained physical activity, and practical details such as a well-fitted hood, effective ventilation openings, or reflective elements for night starts or late finishes.
Insulated Jacket for Winter
During winter trail runs, when temperatures drop significantly and exposure to cold becomes more pronounced, a jacket providing additional thermal insulation can be relevant. Some models incorporate synthetic insulation such as Primaloft, valued for its warmth-to-weight ratio and its performance in damp conditions. This type of jacket helps retain body heat while allowing excess warmth generated during activity to escape. The right choice, however, depends on the conditions, the intensity of the run, and the layering strategy. The goal is to maintain optimal thermal comfort without being overdressed.
Jacket Requirements for the UTMB
For the Ultra-Trail du Mont-Blanc (UTMB), as with other long-distance mountain races, the jacket is a piece of kit that must be chosen with care. It needs to be designed to withstand severe weather, featuring a hood, robust construction, and a membrane that is both waterproof and breathable. Depending on the edition, regulations, and forecasted conditions, the level of requirement may vary. Therefore, it is best to remember that a jacket intended for this type of event must offer a high level of protection, with fully sealed seams, an integrated or manufacturer-approved hood, and consistent construction throughout the garment. Before any race, it is essential to check the official regulations of the specific event, as the exact requirements can vary depending on the race and the expected weather conditions.
Recent Technologies and Innovations
Differences and Benefits of Gore-Tex and PrimaLoft Technologies
Gore-Tex and PrimaLoft refer to two technologies commonly used in technical apparel, each serving different purposes depending on performance needs. One focuses primarily on protection from moisture and wind, while the other is designed to provide thermal insulation.
- Gore-Tex is best known for its technologies combining waterproof protection, wind resistance and breathability. In Gore-Tex waterproof garments, the membrane prevents rain and snow from penetrating while allowing some of the moisture vapour generated during activity to escape. This helps maintain comfort when weather conditions deteriorate.
- PrimaLoft is a synthetic insulation technology valued for its lightweight construction and thermal efficiency. Depending on the version, it can also enhance moisture management and remain effective in cold, damp environments. This type of insulation is therefore ideal when additional warmth is needed without significantly increasing the jacket’s weight.
Eco-friendly Design
The design of trail running jackets is also evolving from an environmental perspective. Increasingly, manufacturers are incorporating recycled materials into fabrics, insulation or components, while striving to maintain high performance levels. Depending on the brand and technologies used, this approach may also involve improving product durability, reducing certain chemical treatments, or adopting manufacturing processes that minimise environmental impact. However, the level of commitment varies from one jacket to another, so it is worth reviewing the information provided by each brand individually.
Trail Running Jacket Care
Washing and Drying Tips
To ensure that your trail running jacket maintains its performance properties, it is crucial to follow the specific washing and drying recommendations provided by the manufacturer. These tips are especially important for jackets made with technical materials like Gore-Tex or Primaloft, which require special care to preserve their waterproofness and breathability:
1. Washing: Most jackets should be washed in cold water with a mild detergent designed for waterproof fabrics. Avoid fabric softeners and bleach, as they can damage the waterproof membrane and alter the fabric's breathability.
2. Rinsing: Make sure that the jacket is thoroughly rinsed to remove all detergent residues, which could inhibit the technical properties of the fabric.
3. Drying: Air dry the jacket or use a low-temperature tumble dryer if recommended. Tumble drying at a low-temperature can revitalize the fabric's water-repellent finish of some jackets.
4. Re-waterproofing: After several washes, it may be necessary to reapply a water-repellent coating to restore the jacket's original waterproofness. Follow the manufacturer's instructions for applying a suitable re-waterproofing spray or lotion.
