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Anticyclonic rotation, or anticyclonic circulation, is atmospheric motion in the direction opposite to a planet's rotation. For Earth, this motion is in a clockwise direction in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. For large-scale weather systems, greater than approximately 500 km , anticyclonic rotation only occurs for high-pressure systems. This is due to how the Coriolis effect acts on high-pressure systems. Large, low-pressure systems, such as tropical cyclones, have cyclonic rotation. Small scale rotating atmospheric features, such as tornadoes, water spouts, and dust devils can have either anticyclonic or cyclonic rotation, since the direction of their spin depends on local forces rather than the Coriolis effect.