What device measures wind speed in meteorology?

An anemometer is the meteorological device used to measure wind speed.

The most familiar design is the cup anemometer, which has cups mounted on horizontal arms around a vertical shaft. Wind pushes the cups around, and the rotation rate is converted into wind speed. Propeller anemometers use a small fan-like rotor, while sonic anemometers calculate wind speed from the travel time of sound pulses between sensors.

Irish scientist John Thomas Romney Robinson invented the cup anemometer in 1846. His design used four cups, although modern instruments commonly use three because that arrangement provides reliable rotation with less mechanical complexity.

An anemometer measures wind speed, not every aspect of wind. Wind direction requires a separate instrument called a wind vane, while a barometer measures atmospheric pressure and a hygrometer measures humidity. Weather stations often combine all of these sensors into one automated observing system.