Cyclone

A cyclone is a large-scale weather system with winds that rotate around a center of low atmospheric pressure.

A cyclone is a large-scale weather system with winds rotating around a centre of low atmospheric pressure. The term is also used regionally for tropical cyclones, especially in the Indian Ocean and South Pacific.

What it is

In meteorology, a cyclone is a rotating system of winds around a low-pressure centre. The word comes from Greek, meaning something coiled or circular. Cyclones can be broad—covering mid-latitude storms—or specific, as in tropical cyclones. Regional usage varies: in the Indian Ocean and South Pacific, “cyclone” is the common name for a tropical cyclone.

How it rotates

Cyclones rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere due to Earth’s rotation. The centre is the lowest-pressure area, often called the eye in mature tropical cyclones. Types include mid-latitude (extratropical) cyclones and stronger tropical cyclones, which are called hurricanes or typhoons in other regions.

Weather and regional notes

Cyclones bring cloudy, unsettled weather: rain, thunderstorms, strong winds, and sometimes snow. In Canada, weather reporting more often uses terms like low-pressure system or extratropical cyclone, but the concept is still relevant in meteorology and climate science. Tropical cyclones are intense storms that form over warm ocean waters.