Trade Winds

Trade winds are the prevailing east to west winds of Earth's equatorial region, blowing from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere, and strengthening in winter. They blow across tropical oceans worldwide, with the notable exception of the northern Indian Ocean, and they play a major role in steering tropical storms across the Atlantic, Pacific, and southern Indian Oceans. They arise from the Hadley cell circulation: air descends around 30 degrees latitude in each hemisphere to form subtropical high-pressure zones, and as that air flows back toward the equator at the surface, the Coriolis effect deflects it westward, producing the characteristic northeasterly and southeasterly patterns in their respective hemispheres. Trade winds carried sailing ships during the Age of Exploration and underwrote the transatlantic and transpacific trade routes that followed.