Wind is measured with an anemometer, a device with cups that spin in moving air.

The longer version

Most instruments for measuring wind speed use rotating cups mounted on arms around a vertical shaft. Moving air pushes harder on the hollow side of each cup than on the rounded side, so the assembly spins, and the rate of rotation is converted into a speed reading.

Other designs use a propeller facing into the flow, or a heated wire whose cooling rate depends on how much air passes over it. Because wind varies from moment to moment, readings are normally averaged over a short interval to give a steadier value. Gusts are recorded separately as the highest brief peak.

Where this entry sits

Clouds, wind, rain, and storms shape daily life in ways that most people barely notice. This collection explains snow, lightning, rainbows, the turning seasons, temperature, the instruments forecasters rely on, and scraps of old weather lore. The full list sits on the Weather and Climate page, where every entry is listed in order.