Winds affect the amount of precipitation received in an area. In contrast to the temporary effects of daily wind shifts, prevailing trade winds have a direct effect on a region's climate.
Contrasts in temperature create winds. Hot air rises, allowing cooler air to flow underneath. This movement of air from cooler to warmer areas is wind. Local winds are created by normal fluctuations in temperature from day to night, but global winds have a more direct effect on the climate of a region.
Because the sun is more intense at the equator, global wind patterns called prevailing winds form. Hotter air at the equator rises and spreads toward the poles. This hotter air is deflected by the rotation of the Earth in a pattern known as the Coriolis effect. Winds are deflected to the right in the northern hemisphere and to the left in the southern hemisphere. Prevailing winds either bring moisture to the land or take it away, depending upon the orientation of the land to the prevailing wind direction.
Ships conducting trade between Europe and the Americas have traditionally used prevailing winds to aid in their travel. For this reason, prevailing winds are also known as trade winds.