Prevailing Winds

Prevailing winds are winds that blow predominantly from a single general direction over a particular point on Earth's surface. The dominant winds are the trends in direction of wind with the highest speed over a particular point on the Earth's surface. A region's prevailing and dominant winds are often affected by global patterns of movement in the Earth's atmosphere. In general, easterly flow exists at low and high latitudes globally. In the mid-latitudes, westerly winds are the rule and their strength is at the mercy of the polar cyclone. In areas where winds tend to be light, the sea breeze/land breeze cycle is the most important to the prevailing wind; in areas which have variable terrain, mountain and valley breezes dominate the wind pattern. Highly elevated surfaces can induce a thermal low, which then augments the environmental wind flow.

Wind roses are tools used to determine the direction of the prevailing wind. Knowledge of the prevailing wind allows the development of prevention strategies for soil erosion of agricultural land, such as across the Great Plains. Sand dunes can orient themselves along, or perpendicular, to the prevailing wind regime within coastal and desert locations. Insects drift along with the prevailing wind, while birds are able to fly more independently of the prevailing wind. Prevailing winds in mountainous locations can lead to significant rainfall gradients within the topography, ranging from wet across windward-facing slopes to desert-like conditions along their lee slopes.