Wind speed describes how fast the air is moving past a certain point. This may be an averaged over a given unit of time, such as miles per hour, or an instantaneous speed, which is reported as a peak wind speed, wind gust or squall.
Wind direction describes the direction on a compass from which the wind emanates, for instance, from the North or from the West.
Wind speed and direction are important for monitoring and predicting weather patterns and global climate. Wind speed and direction have numerous impacts on surface water. These parameters affect rates of evaporation, mixing of surface waters, and the development of seiches and storm surges. Each of these processes has dramatic effects on water quality and water level.
Wind speed is typically reported in miles per hour, knots, or meters per second. One mile per hour is equal to 0.45 meters per second, and 0.87 knots.
Wind direction is typically reported in degrees, and describes the direction from which the wind emanates. A direction of 0 degrees is due North on a compass, and 180 degrees is due South. A direction of 270 degrees would indicate a wind blowing in from the west.
The measurement of wind speed is usually done using a cup or propeller anemometer, which is an instrument with three cups or propellers on a vertical axis. The force of the wind causes the cups or propellers to spin. The spinning rate is proportional to the wind speed
Wind direction is measured by a wind vane that aligns itself with the direction of the wind.