Trade winds blow steadily across tropical oceans and have guided sailors for many centuries.

The longer version

Steady tropical winds blow from the subtropics toward the equator, fed by air that sinks over the horse latitudes and flows back along the surface. The planet's rotation deflects that flow, giving it a consistent easterly component on both sides of the equator.

Because these winds are reliable rather than seasonal, they became the main highways of long-distance sailing for many centuries. Captains could plan voyages around them with confidence, and the belt where the two hemispheres meet, called the doldrums, was known instead for frustrating calms. The belts shift slightly north and south with the seasons.

Where this entry sits

Clouds, wind, rain, and storms shape daily life in ways that most people barely notice. This collection explains snow, lightning, rainbows, the turning seasons, temperature, the instruments forecasters rely on, and scraps of old weather lore. The full list sits on the Weather and Climate page, where every entry is listed in order.