Wind is air in motion. Two factors are necessary to specify wind, speed and direction. It is produced by the uneven heating of the earth's surface by the sun. Since the earth's surface is made of various land and water formations, it absorbs the sun's radiation unevenly. Because of the way Earth rotates, solar light rays heat some parts of Earth's surface more than others. Air at hot spots rises and expands, leaving low pressure beneath it. Air at cold areas cools and falls, creating high pressure. When high-pressure air rushes into a low pressure area, that rush of air is wind.
