Leonardo da Vinci sketched an anemometer to record wind speed and direction.
An anemometer is a device for measuring wind. Leonardo’s design used a flat plate that moved in response to airflow, with a graduated scale allowing the observer to estimate the wind’s strength. The arrangement also helped indicate the direction from which the wind came. He described the instrument in connection with his investigations of flight and atmospheric movement.
Leonardo did not create the modern cup anemometer. That later form, in which cups rotate around a vertical axis, was developed centuries afterward and became common in meteorology. His proposal is better understood as an early scientific measuring instrument rather than a finished standardized device.
The sketch reflects Leonardo’s habit of turning natural observations into mechanical experiments. Wind measurement mattered to his studies of birds, flying machines, sailing, and the behavior of air. The word anemometer comes from the Greek word for wind, anemos.