What weather phenomenon is measured by the Beaufort scale?

The Beaufort scale measures wind force using observed effects and corresponding wind speeds.

Sir Francis Beaufort, a British naval officer, developed the scale in the early 19th century to describe wind conditions at sea. Its original descriptions referred to the behavior of sails and the sea surface. The scale was later adapted for use on land, where observations include effects on trees, flags, and structures.

The modern Beaufort scale commonly runs from force 0, calm, to force 12, hurricane-force wind. It is not a direct instrument reading and should not be confused with the Saffir–Simpson hurricane wind scale or the Fujita tornado scale. Anemometers provide measured wind speed, while Beaufort force translates wind conditions into a standardized descriptive scale.