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a seasonal wind of S Asia that blows from the southwest in summer, bringing heavy rains, and from the northeast in winter

the rainy season when the SW monsoon blows, from about April to October

any wind that changes direction with the seasons

A system of winds that influences the climate of a large area and that reverses direction with the seasons. Monsoons are caused primarily by the much greater annual variation in temperature over large areas of land than over large areas of adjacent ocean water. This variation causes an excess of atmospheric pressure over the continents in the winter, and a deficit in the summer. The disparity causes strong winds to blow between the ocean and the land, bringing heavy seasonal rainfall.

In southern Asia, a wind that is part of such a system and that blows from the southwest in the summer and usually brings heavy rains.