A windsock (also called a wind cone) is a

conical A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines c ...

textile Textile is an Hyponymy and hypernymy, umbrella term that includes various Fiber, fiber-based materials, including fibers, yarns, Staple (textiles)#Filament fiber, filaments, Thread (yarn), threads, different #Fabric, fabric types, etc. At f ...

tube that resembles a giant

sock A sock is a piece of clothing worn on the feet and often covering the ankle or some part of the calf. Some types of shoes or boots are typically worn over socks. In ancient times, socks were made from leather or matted animal hair. In the la ...

. It can be used as a basic indicator of

wind speed In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer. Wind speed ...

and direction, or as decoration. They are typically used at

airport An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surfa ...

s to show the direction and strength of the wind to pilots, and at

chemical plant A chemical plant is an industrial process plant that manufactures (or otherwise processes) chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transfo ...

s where there is risk of gaseous leakage. They are also sometimes located alongside

highway A highway is any public or private road or other public way on land. It is used for major roads, but also includes other public roads and public tracks. In some areas of the United States, it is used as an equivalent term to controlled-access ...

s at windy locations. At many

s, windsocks are externally or internally lit at

night Night (also described as night time, unconventionally spelled as "nite") is the period of ambient darkness from sunset to sunrise during each 24-hour day, when the Sun is below the horizon. The exact time when night begins and ends depends ...

Function

Wind direction is the direction in which the windsock is pointing. (Wind directions are conventionally specified as the compass point from which the wind originates; so a windsock pointing due

north North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north ...

indicates a

south South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

erly wind). Wind speed is indicated by the windsock's

angle In Euclidean geometry, an angle is the figure formed by two rays, called the '' sides'' of the angle, sharing a common endpoint, called the ''vertex'' of the angle. Angles formed by two rays lie in the plane that contains the rays. Angles ...

relative to the mounting pole; in low winds it droops; in high winds it flies horizontally. Alternating stripes of high visibility orange and white were initially used to help to estimate wind speed, with each stripe adding 3

knots A knot is a fastening in rope or interwoven lines. Knot may also refer to: Places * Knot, Nancowry, a village in India Archaeology * Knot of Isis (tyet), symbol of welfare/life. * Minoan snake goddess figurines#Sacral knot Arts, entertainme ...

to the estimated speed. However, some circular frame mountings cause windsocks to be held open at one end, indicating a velocity of 3 knots even when it is not present. A fully extended windsock suggests a wind speed of or greater.

Standards

Per FAA standards, a properly functioning windsock orients itself to a breeze of at least and fully extends in wind of . Per

Transport Canada Transport Canada (french: Transports Canada) is the department within the Government of Canada responsible for developing regulations, policies and services of road, rail, marine and air transportation in Canada. It is part of the Transporta ...

standards, a wind fully extends the windsock; a wind raises it to 5° below the horizontal; and a wind raises it to 30° below the horizontal.

ICAO The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international a ...

standards specify a truncated cone-shaped windsock at least 3.6 m long and 0.9 m in diameter at the large end. It should be visible and understandable from an altitude of 300 m and ideally be of a single colour. If it is necessary to use two colours, they should ideally be orange and white arranged in five alternating bands, with the first and last darker in tone. In wind speeds of or more they must indicate wind direction to within ±5°.

References

Airport infrastructure Meteorological instrumentation and equipment Socks {{Climate-stub

Function

Standards

See also

References