For maximum comfort in the outdoors, it is important to wear appropriate clothing in an efficient way. Proper layering is the best way to achieve this. Think of dressing your body with layers the way you would use to construct the layers of a house. Begin with a base layer, like the walls, followed by an insulating layer to regulate temperature, then an outer layer to keep out the elements. The base layer in this clothing system is a long underwear piece that transfers moisture from your body and wicks it outward to keep you dry. The insulating layer is a fleece or a synthetic-filled jacket that traps heat to keep your warm. The outer layer is a jacket with wind and/or water repellency to protect you from wet and windy environments.
Long underwear worn next to the skin is used as a base layer and provides both moisture management and temperature control. The most widely used fabrics are polyester or silk for their insulation, wicking and quick drying ability.
Silk-weight Versatile Quickest Dry Time
Mid-weight Cold Weather Good Insulation; still fits well under clothes
Expedition-weight Extreme Cold Most Insulation; higher bulk
Pants and shirts that are worn next to the skin or over a base layer are mid layers that regulate temperature and exposure to the elements. Cold weather fabrics, such as polyester, nylon, and wool, provide good insulation, wicking ability and quick drying time. Hot weather fabrics, such as polyester and nylon provide good sun protection and a quick drying time. Note that cotton use should only be considered for warm and dry climates. Cotton fibers absorb water which reduced their insulation ability and take longer to dry. Nylon hiking shirts and pants are for good breathability, sun protection and fast drying. Fleece shirts and pants are useful for cold weather insulation and fast drying. Finally, mid layer accessories include hats, gloves, and socks.
Outer shell jackets and pants are outer layers that provide protection from wet weather conditions.
Soft shells that are water resistant, windproof, and/or highly breathable offer some protection from light rain and snow. Hard shells are waterproof, windproof, and/or breathable protection from rain and snow.