Wind Speed (or Wind Velocity) is an air moving from high to low pressure, usually due to changes in temperature that is the horizontal movement of air specified by its speed and direction measured over the land surface at a height of 10 m above ground level. The normal unit of wind speed is the knot, and the wind direction is measured relative to true north (not magnetic north) reported from where the wind is blowing. The Wind Speed is defined as the two minute average speed in knots. The gust speed and direction are defined by the maximum three second average wind speed occurring in any period. A gale is defined as a surface wind of mean speed of 34-40 knots, averaged over a period of ten minutes.

Related Definitions in the Project: The Wind Energy