Whether you're hiking, running trail or skiing, wearing the wrong kit can quickly become a problem. Too hot, too cold, the wrong clothes, or simply too much gear — the layering system is the ideal solution.
What is the layering system?
The layering system is widely used in outdoor sports such as hiking, mountaineering, trail running, road running and skiing. Like the layers of an onion, it involves stacking multiple layers of clothing rather than wearing a single thick one. This allows you to optimise performance through better thermal regulation.
The layering system has many advantages. The most important is its adaptability and comfort. You can remove or add a layer depending on effort and weather. The air trapped between layers also helps improve insulation, providing greater thermal efficiency. Moisture is better managed, which prevents the body from chilling. Finally, the same kit can adapt to different seasons and activities — ideal for outdoor sports enthusiasts.
Traditionally, the layering system consists of three layers, each with a different function. The first is a breathable base layer, the second an insulating mid layer, and the third a protective outer layer. In extreme conditions, it is possible to stack up to 4 or 5 layers.
The first layer
The first layer, or base layer, is breathable. Its role is to wick away moisture. During physical effort, the body produces moisture. If this stays in contact with the skin, it causes the body to cool down. Thanks to the thermal regulation provided by the first layer, the skin stays dry and the body retains its warmth. If you're wondering what to wear for hiking, a breathable first layer is an absolute essential.
The first layer forms the foundation of the layering system. The materials used must therefore be chosen carefully. Synthetic fibres (polyester, polyamide, elastane) are a solid option. They offer good breathability, dry quickly and are affordable, though they can retain odours. Merino wool provides excellent thermal regulation, has antibacterial properties, and is soft and comfortable. It is, however, more expensive and less durable.
For a good balance of warmth, comfort, moisture management and durability, you can choose garments that blend merino wool with synthetic materials. In any case, avoid cotton, which retains moisture.
When it comes to garment types, several options are available depending on your activity and the weather. In winter, thermal base layers are recommended. For a summer or mid-season hike, you can opt for short- or long-sleeved hiking t-shirts. Wear them close to the body — not too tight — for maximum effectiveness.
The second layer
The second layer, also known as the mid layer, is insulating. Its primary function is to retain body heat by trapping air between the fibres and the fabric. It also moves moisture away from the base layer towards the outer layer. In the layering system, it is the layer you add or remove most easily.
Just like the first layer, the second layer can be made from a variety of materials. Fleece, a synthetic material, is lightweight, warm, breathable, quick-drying and affordable. It does, however, offer limited wind and rain resistance. Synthetic insulated jackets provide good insulation even when wet, and dry quickly. Goose or duck down jackets deliver exceptional warmth and have the advantage of being lightweight and compressible. They are, however, more sensitive to moisture and come at a higher price.
If you're heading out hiking, fleece jackets are a must. They're highly valued in dry, cool conditions, especially during bivvy evenings. In extreme cold and dry climates, down jackets — particularly those filled with down — are more suitable thanks to their maximum insulation. Finally, softshell jackets offer a good compromise between warmth and protection. They combine insulation, wind resistance and breathability, making them perfect for mid-season.
The third layer
The third layer, or outer layer, is protective. In the layering system, it is the layer in direct contact with the outside. Its job is to shield against the elements — wind, rain, snow and extreme cold. It must also preserve the effectiveness of the two layers underneath.
Most outer layers are waterproof and breathable. For this, we recommend choosing a technical membrane such as Gore-Tex® or Cimalp's Ultrashell® technology, which blocks rain while preventing moisture build-up inside. Some garments feature a DWR (Durable Water Repellent) treatment to make rain bead off the surface. Others use a windproof fabric — lighter and designed primarily to block wind. This has the advantage of being extremely lightweight, but is not effective in prolonged heavy rain.
The right third layer depends primarily on your activity. Hardshell waterproof jackets are essential for long hikes, trekking and mountaineering. They perform in all conditions and act as a true outer shell. Windproof jackets are perfect for fast hiking or trail. They are ultra-compact and pack away easily. Finally, ponchos or rain capes are useful for occasional outings. They protect both you and your pack, are budget-friendly, but are less suited to strong winds and less breathable.
The layering system is one of the best ways to dress for outdoor activities. By following the three-layer principle, you'll be ready to hike, run trail or ski in complete comfort. And for even more protection, don't forget to keep your extremities well covered against the cold.
