Cyclonic rotation or cyclonic circulation is the atmospheric motion in the same direction as a planet's rotation, as opposed to anticyclonic rotation. In the case of Earth's rotation, the Coriolis effect causes cyclonic rotation to be in a counterclockwise direction in the Northern Hemisphere and clockwise in the Southern Hemisphere. A closed area of winds rotating cyclonically is known as a cyclone.
Cyclonic rotation is characteristic of the vast majority of violent tornadoes and of mesocyclones, which are regions of rotation of storm-scale, 2-6 miles across, an area that is much larger than that of any tornado that may be in it.