A windsock 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