An anemometer is a device that measures wind speed. The most common type looks like a small windmill with three or four cups mounted on arms that spin around a vertical pole. As wind pushes against the cups, they rotate faster or slower depending on how hard the wind is blowing. The anemometer counts these rotations and calculates the wind's speed, usually in miles per hour or meters per second.

Meteorologists use anemometers at weather stations to track wind patterns and predict storms. Sailors rely on them to know if conditions are safe for leaving port. Engineers use them when designing tall buildings or bridges, since understanding typical wind speeds helps them create structures that won't sway dangerously. You might see small anemometers mounted on boats, at airports where pilots need to know wind conditions before takeoff, or on rooftops where scientists study local weather patterns.

While cup anemometers are most recognizable, other types use spinning propellers, ultrasonic sensors, or even heated wires that cool differently depending on wind speed. Whether simple or sophisticated, they all serve the same purpose: turning invisible, moving air into measurable numbers that help people make smart decisions about weather and safety.