Wind speed measurements are often made using a cup anemometer three cups that rotate around a vertical axis with the revolutions per minute recorded electronically to give wind speed. Cup anemometers are used almost everywhere. The ratio of wind velocity to that of the turning cups depends on the cup dimensions and arm length, and has a value between two and slightly more than three. Generally, an anemometer has a wind vane attached to detect the wind direction.
The newer laser anemometers detect coherent light reflected from the air molecules to get speed, and ultrasonic anemometers detect the phase shifting of sound. A hot wire anemometer uses temperature differences between wires placed in the wind and in the wind's lee to determine wind speed. Special models with electrically heated shafts and cups may be used in arctic areas. Non-mechanical anemometers are less sensitive to icing.