Hats are worn everyday, big, small, medium. All kind of hats: cowboy, ski, winter, summer, spring, fall.
A hat is a head covering. It can be worn for protection against the elements, for ceremonial or religious reasons, for safety, or as a fashion accessory. In the past, hats were an indicator of social status. In the military, they may denote nationality, branch of service, rank and/or regiment