Monsoon

A monsoon is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation, now used more broadly to describe seasonal changes in atmospheric circulation and precipitation tied to the annual latitudinal oscillation of the Intertropical Convergence Zone across the equator. The term usually refers to the rainy phase of this seasonal pattern, though a dry phase exists as well, and it is also used for locally heavy but short-lived rains. The major monsoon systems of the world are the West African, South Asian-Australian, North American and South American monsoons; the term itself entered English in British India, describing the seasonal winds off the Bay of Bengal and Arabian Sea that bring heavy rainfall to the region.