The primary purpose of clothing is to warm the wearer. In hot climates this function is minimal, while in very cold climates it is very high. Shelter usually reduces this functional need for clothing. For example, coats, gloves, etc. would normally be removed when entering a warm home. The need for protection from precipitation, such as rain and snow, and wind are further considerations.

Clothes also reduce the level of risk during an activity, such as work or sport. Clothing at times is worn as protection from environmental hazards, such as insects, noxious chemicals, weapons, and contact with abrasive substances. Clothing can protect against many things that might injure the naked human body. Conversely, clothing may protect the environment from the clothing wearer, as for example wearing of medical scrubs.

Humans have shown extreme inventiveness in devising clothing solutions to environmental hazards and the distinction between clothing and other protective equipment is not always clear-cut; examples include space suit, air conditioned clothing, armor, diving suit, swimsuit, bee-keeper's protective clothing, motorcycle leathers, high-visibility clothing, and protective clothing.