So, the points that are near the equator travel faster. As air moves toward the equator, it reaches faster-moving points on the earth's surface. Because these surface points are moving eastward faster than the air, a person standing on the earth feels a wind blowing westward. This calm belt is called the doldrums. Some of the air that rises at the equator returns to the earth's surface at about 30 north and south latitude.
Air moving downward there produces no wind.
These areas are called the horse latitudes, possibly because many horses died on sailing ships that were stalled by the lack of wind there. Two other kinds of prevailing winds result from the general circulation in the atmosphere. The prevailing westerlies blow somewhat from west to east in two belts between latitudes of about 30 and 60 north and south of the equator. These winds result from surface air moving away from the equator and reaching slower-moving points nearer the poles. Prevailing westerlies carry weather eastward across the northern United States and southern Canada.