The basis of layering fashion
The beauty of this simple concept is that you can quickly adjust it based on activity level and changes in the weather. Each layer has its own function. The base layer (against your skin) manages moisture; the insulating layer protects you from the cold; the outer layer protects you from wind and rain. You simply add or remove layers as needed.
Simple, right? Well, we have some more expert tips below about these different layers that will make your next adventure even more enjoyable.
This is the layer against the skin. It helps to regulate your body temperature by wicking moisture away from your skin to the outer layers.
By staying dry, you keep your body temperature cool in the summer and prevent hypothermia in the winter. If you've ever worn a cotton T-shirt under your rain jacket while walking, you probably remember feeling wet and clammy, even though you didn't get wet from the rain itself.
Cotton is a fabric that retains moisture and can make you feel cold.
For comfort in the outdoors, your base layer should be made of merino wool (popular with brands like Icebreaker), synthetic fabrics (polyesters such as Polartec Power Dry® or Patagonia Capilene®), or, for less active applications, silk. Instead of absorbing moisture, these fabrics transport (or "wick") perspiration away from your skin and spread it to the outside where it can evaporate through your rain jacket. The result: You stay drier, even when you sweat, and your shirt dries faster afterwards.
Examples:
A base layer can be anything from underwear and sports bras to long underwear sets to tights and T-shirts. This layer can fit snugly or loosely. For cold conditions, thermal underwear is available in lightweight, midweight, and expedition weights. Choose the weight that best suits your planned activity and the temperature you will experience there.
The mid layer: Insulation
The insulating layer helps you retain warmth by keeping a small layer of warmed air close to the body.
Natural fibres such as wool and goose down are excellent insulators. Sweaters and shirts made of merino wool provide soft, reliable warmth and continue to insulate even when wet.
For very cold and dry conditions, goose down is the best. It offers an unmatched ratio of warmth to weight and is highly compressible. The biggest drawback of down is that it must stay dry to maintain its insulating properties.
Classic fleece such as Polartec® 100, 200 or Thermal Pro polyester and other synthetic fabrics like Thinsulate® provide warmth for a variety of conditions. They are lightweight and breathable and insulate even when wet. They also dry faster and have a higher warmth-to-weight ratio than wool. The main disadvantages of classic fleece are its breathability and bulk (it is less compressible than other fabrics and fills a backpack more quickly).
Like thermal underwear, fleece tops are available in 3 weights:
Lightweight
for aerobic activities or a mild local climate
Midweight
for moderate activities or temperate climates
Expedition weight
for low activity or cold/winter climates
Examples:
For high-energy activities such as cross-country skiing, cycling or running, it is best to choose lightweight fleece (Polartec 100 or Power Dry) to prevent overheating. For cold conditions, try thicker fleece like Polartec 200 or 300.
Wind fleece such as Polartec WindPro® polyester or Gore WindStopper® gives fleece a high degree of wind resistance. How? It uses a hidden membrane that does not affect breathability.
The outer layer: Protection against the elements
The outer layer protects you from wind, rain or snow. Shells range from expensive mountaineering jackets to simple windproof jackets. Most allow at least some perspiration moisture to escape; almost all shells are treated with a durable water-repellent (DWR) finish, so water rolls off the fabric.
An outer layer is an important component in bad weather, because if wind and water can penetrate to your inner layers, you will get cold. Moreover, perspiration cannot evaporate without proper ventilation, but condenses on the inside of the outer layer and your base layer and mid-layer will become wet from your own sweat.
Another consideration for your outer layer is the fit. The outer layer should be loose enough to easily fit over other layers and not restrict your freedom of movement. A too thick fleece under a fitted rain jacket will not feel pleasant, therefore rain jackets are often slightly too large when you buy them in your usual size.
Waterproof/breathable shells
These are the most functional (but also the most expensive) choices. They are best for wet, cool conditions and activities in the mountains. Shells with laminated membranes such as Gore-Tex and eVent offer top performance.
Water-resistant/breathable shells
These are most suitable for light precipitation and high activity levels. They are less expensive than waterproof/breathable shells and usually made from tightly woven fabrics (such as mini-ripstop nylon) to block wind and light rain.
Soft shells
These emphasise breathability. Most have stretch fabric or panels for extra comfort during aerobic activities. Many offer both a shell and insulation, so they combine 2 layers in softshells for cold and mild weather conditions.
Waterproof/non-breathable shells
These economical shells are ideal for rainy days with light activity (e.g. fishing, watching sports). They are usually made of sturdy nylon with a polyurethane coating that is waterproof and windproof.
Insulated shells
Some shells have an insulation layer built in, such as fleece, making them suitable for cold, wet conditions, but not as versatile for layering in changing temperatures.
Note
When layering, it’s about keeping your body temperature at a comfortable level. Try to avoid sweating at all times, especially in colder areas.
Zips help to regulate your body temperature during a walk. Some shells even have zips under the armpits, which really helps to regulate your body heat.