Britannica Sources used in this answer

How do trade winds form near subtropical high-pressure belts?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

World map with continents shaded in colors representing climate zones, from warm reds and yellows near the equator to cool blues and whites at the poles. — Climate Even in our warming world, there will be some chilly evenings.

Trade winds form as part of the Hadley cell, a large-scale atmospheric circulation pattern. The process begins near the Equator, where warm air rises, creating a region of low pressure. This air travels toward the poles at high altitudes before cooling and descending at approximately 30° latitude, forming semipermanent subtropical high-pressure belts.123

Upon reaching the surface in these high-pressure regions, the air diverges. The portion of air that flows equatorward is deflected by the Coriolis effect—an apparent force caused by the Earth's rotation. This deflection directs the air toward the west, resulting in the persistent trade winds that blow from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere. These winds eventually converge in the intertropical convergence zone (ITCZ) near the Equator, where the air rises to continue the cycle.3245