Layering is comprised of insulating garments to create an effective and efficient cold weather system. The purpose of layering is to keep you warm and dry. Why is dry important? Because when the body is wet it is cooled, and in cold weather a quickly cooling body could equal hypothermia or frostbite. Layering is important because it allows the regulation of body heat retained. This is achieved by adding or taking away layers. An effective and efficient system allows the user to take pieces off when temperatures rise and put layers on when temperatures drop. There are many different types layering pieces and sometimes their usefulness in some situations is not always clear.

In order to maximize effectiveness of this system, here you have an understanding of the 3 components:

1. Base Layer - Next to skin, this is also sometimes thermal underwear.
2. Mid Layer- Different layers of insulation(shirts, sweaters, jackets, pants).
3. Outer Layer - This is the shell layer. The piece that covers and protects the first two layers.