A windsock or wind cone is a conical textile tube designed to indicate wind direction and relative wind speed. Windsocks typically are used at airports and at chemical plants where there is risk of gaseous leakage. They are sometimes located alongside highways at windy locations.
Wind direction is the opposite of the direction in which the windsock is pointing (note that wind directions are conventionally specified as being the compass point from which the wind originates; so a windsock pointing due north indicates a southerly wind). Windspeed is indicated by the windsock's angle relative to the mounting pole; in low winds, the windsock droops; in high winds it flies horizontally.
Per FAA standards referenced below, a 15 knot (17mph) wind will fully extend the windsock. A 3 knot (3.5mph) breeze will cause the windsock to orient itself according to the wind.
At many airports windsocks are lighted at night, either by flood lights on top surrounding it or with one mounted on the pole shining inside it.
Windsocks originated in China and Japan, where they were considered a symbol of good luck and longevity. On Children's Day they display traditional Japanese windsocks, or koinobori.
- FAA Specification for Wind Cone Assemblies FAA Advisory Circular 150/5345-27D (PDF 447KB)
windsock in Danish: Vindpose
windsock in German: Windsack
windsock in Spanish: Manga de viento
windsock in Persian: جوراب باد
windsock in French: Manche à air
windsock in Dutch: Windzak
windsock in Norwegian: Vindpølse
windsock in Polish: Rękaw (wskaźnik wiatru)
windsock in Portuguese: Biruta
windsock in Finnish: Tuulipussi