A wind vane (also known as a weathervane) is an instrument that tells you the wind direction. Specifically, a wind vane lets you know what direction the wind is coming from. In other words, a “southwest” reading on a wind vane means that the wind is originating southwest of your location, and heading in a northeast direction.
How Does a Wind Vane Work?
While many weather instruments can be somewhat complex in design, wind vanes are typically quite simple. In most cases, a fin will sit on top, or hang below, a spindle which allows the fin to rotate on a horizontal plane. Like anemometers (which measure wind speed), situating the wind vane on a horizontal plane allows it to measure activity regardless of wind direction.
The fin itself will generally feature a point on one end and a long and broad shape at the other. This will ensure the fin always points in the direction the wind is originating from.
What Are the Types of Wind Vanes?
There are three primary types of wind vanes: the classic weathervane, wind sock, and digital wind vane.
Weathervane – In use for centuries, these are the type often seen on top of barns, cathedrals, and a variety of other buildings. Since weathervanes are also used for decorative purposes (in addition to functional applications), they can take on a variety of shapes and styles. The classic style features a fin in the shape of a rooster, but a variety of other fin shapes can be featured. They can include the silhouette of a noteworthy person, a ship, fish, tractor, or a simple arrow.
Typically, beneath the fin, you’ll see situated four horizontal posts that read “N,” “S,” “E,” and “W” (north, south, east, and west) to help the viewer determine the wind direction. Reading a weathervane is easy. Whichever direction the fin is pointing will indicate where the wind is coming from.
Wind Sock – This type of wind vane is primarily seen in airports, near runways. While a wind sock determines the wind direction, it generally does not indicate a north/south/east/west direction. However, based on how much the sock is inflated, the viewer can estimate the strength of the wind.
This is helpful because, for example, a pilot needs to know the wind direction and strength to help him or her adjust for the wind when landing or taking off. A wind sock can also be beneficial at a golf course, marina, baseball field, or any other location where knowing the wind direction and strength is useful when participating in an activity.
Digital Wind Vane – A digital wind vane shares many basic design elements with a classic weathervane, but is significantly more sophisticated. Quite often, a digital wind vane is seen as a component of a weather station, which will also measure conditions such as wind speed, temperature, humidity, barometric pressure, and sometimes rainfall.
A digital wind vane will either hang from a weather station sensor’s underside, or sit atop a pole or housing of some sort, and rotate on a spindle. At the end of the spindle will usually be an optical sensor that allows a digital processor to know the wind direction, typically up to 16 positions. The reading is sent to a digital display where the wind direction is shown on a circular graphic called a wind rose. Oftentimes, the wind rose will show (in the form of arrows) the current wind direction, as well as the previous two readings.
Why is it Beneficial to Have a Wind Vane?
A wind vane can provide a variety of uses. These can include enhanced enjoyment of a recreational activity, safety, protection of property, and the general enjoyment of weather observation.