Leonardo da Vinci designed an anemometer, an instrument for measuring wind speed.
His design used a plate or surface that moved in response to wind, with a scale that could indicate the strength of the airflow. Leonardo studied the device while investigating flight, air movement, and the behavior of the atmosphere. The instrument was intended to help compare wind conditions rather than simply show wind direction.
Anemometers later developed into many forms, including cup, vane, and hot-wire instruments. Modern weather stations commonly use rotating cups or electronic sensors, but the basic purpose remains the same: measuring how fast air moves. Wind vanes, by contrast, primarily indicate direction.
Leonardo’s anemometer should not be confused with a barometer. A barometer measures atmospheric pressure, while an anemometer measures wind speed. His design was part of a broader program of observation in which he tried to turn natural phenomena into measurable quantities, an approach that distinguished his engineering notebooks from purely imaginative sketches.