Because many outdoor sports and activities take place in all seasons and all conditions, special clothing is sometimes necessary to combat the elements. Waterproof outerwear is specially designed clothing that combats water from the elements — such as rain or snow, or even standing water such as lakes or rivers — to keep the wearer dry and warm in harsh conditions. Waterproof outerwear includes jackets, pants, shirts, boots, hats, and any other type of clothing that might keep the wearer warm and dry.
Many types of waterproof outerwear were made of simple plastics, polyesters or nylons in the past. These materials were waterproof and strong, but they were not breathable. This meant that the wearer would be protected from the elements, but he or she would also sweat because heat and moisture from the body could not escape the material. This was counter-productive, since the whole idea behind waterproof outerwear is to keep the skin warm and dry.
As a result, special breathable fabrics were developed. Perhaps the most well known material is GORE-TEX, which is a specially designed fabric that is comprised of several layers: the outer layer is a tough, often tear-resistant nylon or polyester; the middle layer is Teflon (technically known as polytetrafluoroethylene) fabric that repels water from the outside while still allowing moisture from the body to escape. This keeps the body warm and dry. Another inner layer protects the easily damaged Teflon layer from deterioration by sweat or repetitive movement.
It is important to note that there is a difference between waterproof outerwear and water-resistant outerwear. Waterproof outerwear is designed to completely protect the body from moisture; in other words, water should not be allowed to pass through the material and make contact with the skin at any time. Water-resistant outerwear repels water to a certain degree, but it is not fully waterproof; eventually, water will penetrate the material and make contact with the skin. Water-resistant materials are useful for lighter applications, such as light rain showers or light snow. Waterproof outerwear is designed for more extreme conditions, such as heavy downpours, heavy snow, or other conditions in which water is a persistent and heavy presence.
Waterproof clothing is commonly seen anywhere outdoor activities are common. Skiers use waterproof jackets and pants; mountaineers are constantly exposed to harsh elements and therefore wear waterproof clothing. Waterproof hiking boots are common among hikers, and other types of waterproof footwear is common in construction and other outdoor professions.