Leonardo da Vinci designed an anemometer, an instrument for measuring wind speed.
His version used a light, conical plate that moved upward or downward according to the force of the wind. A graduated scale beside the plate allowed the observer to estimate wind strength. Leonardo included the device in his studies of flight and atmospheric conditions, because understanding wind was important to his investigations of birds and flying machines.
An anemometer is not the same as a wind vane. A wind vane shows the direction from which wind comes, while an anemometer measures its speed. Modern instruments commonly use rotating cups, propellers, or ultrasonic sensors, but the purpose remains similar.
Leonardo's design belongs to a long history of experimental meteorological instruments. It did not provide the electronic precision of contemporary sensors, yet it translated an invisible force into a visible mechanical reading. That practical measuring approach was typical of his notebooks, where observation and engineering were closely connected.