Wind Direction and Speed Indicator:
Wind direction is reported by the direction from which it originates. For example, a northerly wind blows from the north to the south. Wind direction is usually reported in cardinal directions or in azimuth degrees. For example, a wind coming from the south is given as 180 degrees; one from the east is 90 degrees. An example of a Wind Speed Indicator is the anemometer. It is a device used for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, which means wind, and is used to describe any wind speed measurement instrument used in meteorology. The first known description of an anemometer was given by Leon Battista Alberti in 1450.
As shown on the left: A knot is a unit of speed. It is abbreviated kt or kn. It is a non-SI unit accepted for use with the SI. It is used around the world in meteorology and for maritime and aviation purposes.