Definition
A device installed at an airport that visually shows pilots the direction from which the surface wind is blowing. Common forms include the wind sock (a tapered fabric tube on a swiveling mast), the wind tee, and the tetrahedron. All three pivot freely and align themselves with the wind so the open or larger end faces into the wind.
Plain English
A simple visual marker at an airport that shows which way the wind is blowing along the ground, so pilots know which runway to use for takeoff and landing.
Context Anchor
Seen on or near an airport when checking surface wind before taxi, takeoff, landing, or while overflying an unfamiliar airport.
Derivation
Wind comes from an old English word for moving air. Direction comes from a Latin word meaning “to guide or point straight.” Indicator comes from a Latin word meaning “to point out.” Together, the phrase means a device that points out the wind’s direction.
Why Pilots Care
Pilots rely on it to choose the correct runway for takeoff and landing and to anticipate crosswind effects on aircraft handling.
Analogy
Like a flag or streamer on a pole that stretches out fully in the direction the wind is moving.
Intuition Check
Do not read “wind direction” as the direction the wind is traveling toward. In aviation, wind direction means the direction the wind is coming from.
Example Sentence 1
On downwind, the pilot glanced at the wind sock by the segmented circle and confirmed Runway 27 was still favored.
Example Sentence 2
At uncontrolled fields the wind direction indicator helps determine which runway offers the best headwind component.