Warmth is provided by three layers: Base: polyester, silk, or any material that can drain moisture away from your skin. Simply do not wear a cotton shirt as your base layer. It will collect moisture, but it will not evaporate. Next, wear a lightweight fleece for comfort. Finally, wear a heavy wool sweater to keep warm in cold conditions. Basics: The first thing to know about layering is that each layer adds weight, so you need to add more layers as the temperature drops. A light jacket or coat can be worn over a simple T-shirt and shorts for a quick way to stay warm while still feeling comfortable. Larger items such as down jackets and quilts are used for warmth on cold nights when you cannot go inside. There are different types of fabrics used for clothing layers. Each type has its own characteristics that make them suitable for certain conditions. For example, cotton is a good choice for hot weather because it breathes well and doesn't cling to yourself. On cold days, consider using wool or acrylic fibers because they hold their heat longer than cotton does. You may also want to choose natural fibers over synthetics because they're better for the environment. The amount of layers you wear depends on the temperature and how long you plan to be outside.