The basic function of clothing is to keep you dry, warm and protected. By dressing in several thin layers, you can easily regulate you clothing depending on weather and wind. The layering principle and how the different characteristics of materials can be used to create a nice and comfortable stay in the mountains are explained.

First layer
The first layer is there to keep you dry from inside, making the choice of material in clothing nearest to the body very important.

Cotton absorbs moisture well, but both cools and chafes when wet. This material is not recommended.

 Synthetic underwear, so-called super underwear, has a slightly different construction. Its basic function is to transport moisture and excess heat away to a layer further away from the body that absorbs. This works very well during extreme exertion when you sweat a lot, but it requires a mid layer that absorbs moisture. To maintain its function and avoid the smell of sweat, the garment must be rinsed/washed often, preferably daily. Specially designed for physical activity and if you sweat easily and a lot.

 Wool and wool terry cloth (mixed material) absorb and disperse moisture in the material and have the capacity to warm even when wet. The function of wool is not affected if the garment is used without washing during longer periods and wool does not smell. This makes wool an excellent choice when the activity is ongoing for a long period with breaks outdoors, such as when mountain hiking or ski touring.

Second layer
The second layer will absorb the moisture that the first layer transports away from the body; this is a vital capacity. A pure synthetic material does not have this capacity.

Many super underwear combine the first two functions, for example by mixing in wool that is woven into the garment’s outer layer. 

A cotton skirt can work, since it absorbs moisture well, but not if you sweat easily and a lot and at the same time rest outdoors. The cotton will then cool you down too much.

Wool that absorbs moisture and warms, even when wet, is also excellent as a second layer.

Third layer
The third layer warms the most and is often the regulating layer. You wear it during low intensity activity and when resting and remove it during high exertion. This way, you retain body warmth when standing still and avoid becoming too warm and sweaty when moving. The usual material in the third layer is fleece and wool.

Fleece
A synthetic fibre is constructed porous to be airy. Your body heat warms air in the material, but the material does not have its own warming capacity. Well suited for when you change often between activity and sitting still. Fleece is less suitable if you sit for longer periods.

Wool
An airy wool sweater will often become too warm during an activity, though during cold breaks and other still activities, it is a comfortable, warm friend. The wool fibre has a warming capacity in itself, meaning that it is not dependent on excess heat from your body to keep warm. Wool is well suited for ice fishing, bivouacking and long breaks outdoors during cold and windy winter days.

Fourth layer
The fourth layer is the outer, protecting layer. It should first and foremost provide protection against wind and precipitation and give exposed body parts, such as the face, protection from the cold. Another important function of the fourth layer is to work as ventilation that regulates heat. It places demands on the jacket as a whole and details in its design and functionality.

A fourth layer garment should be roomy and protect sensitive body parts, such as head, neck, wrists, waist and ankles. A traditional anorak, or a shell garment for use in the mountains with a jacket and pants that protect against wind, rain and snow, should have a reliable hood, generally with a fur collar or “wind sleeve” to protect the face. It is ample in length and has functional closures in the front, collar and wrists, as well as a drawstring closure in the waist and lower down on the jacket. By loosening the closures, excess heat is vented away. In the end, you keep warm.

Always use a hat and you won’t freeze your feet. When wearing a hat, body heat does not disappear via the head and thus you also keep your feet warm.

Material
The classic anorak in various cotton blends and the modern shell garment in synthetic, for example Gore-Tex, both have their advantages and disadvantages.

Tightly woven cotton/synthetic
The traditional anorak works best in winter with a dry cold and wind. It is soft and versatile and does not cool as long as it is dry. It lets excess heat through, but it also lets in wet after some time in damp, wet weather. Excellent when used in minus degrees.

Synthetic shell garment (for example Gore-Tex)
Synthetic shell material is apparently totally tight, but it has small, small holes that are large enough to release heat in the form of water vapour from inside, and small enough to not allow water from outside. The material therefore can handle wet better than cotton and be usable year-round. But what is an advantage in certain layers can also be a disadvantage, which is clearly noticed during cold and windy winter days. Cold makes it easy for the body’s excess heat to condense before it can press its way out through the garment. It will then be humid, occasionally even as a coating of ice, on the inside of the shell garment. One way to counteract this is to put on a sweater outside the shell garment. The garment then does not cool as much and condensation on the inside is avoided.

 
Fifth layer
The fifth layer is an extra layer for breaks and longer activities when sitting still. A down jacket, vest or thick sweater can then be useful.