Weather vanes have long been used as a way to forecast weather by determining which way the wind is blowing. Today, they can still be found on the roofs of homes, barns and silos in many shapes and made from many materials. Some weather vanes are even collectors' items.
Earliest Weather Vane
The earliest weather vane was affixed to the Tower of the Winds in Athens, Greece. The tower was built in 48 B.C. by the astronomer Andronicus. The weather vane, in the shape of the Greek god Triton (the head and torso of a human, and the tail of a fish) was between 4 and 8 feet long.
The Vikings also used weather vanes, and archaeologists have found some dating back to the 9th century. Typically made of bronze, these weather vanes were placed on ships and churches.
During the 9th century, the pope decreed that every church should have a rooster on its steeple. This was due to the prophecy of Jesus in the book of Luke, stating that the cock would not crow on the morning after the Last Supper: "And he said, I tell you, Peter, the cock shall not crow this day, before that you shall thrice deny that you know me" (Luke 22:34). Weather vanes in the shape of roosters went up on the steeples of churches all over Europe.
Simple weather vanes are made of two arrows that denote wind direction. Modern weather vanes are connected to reading stations that produce weather data. To be accurate, these tools must be placed high above the ground and at a considerable distance from tall buildings or trees that can mitigate the strength of the wind. Even with nothing more than a weather vane and a look at the sky above, a simple short-range forecast can be made.
Weight is disbursed equally on both sides of the weather vane, but the surface area is bigger on one side, so that the pointer can move on the axis with the wind. The larger surface area is blown by strong winds, and moves in the opposite direction. The pointer then swings to point the true direction of the wind. Weather vanes with large animals or designs are not always accurate, especially in light winds.
Weather Vanes Today
Weather vanes are still placed on the tops of houses and churches, but mainly as decoration. There are numerous shapes and sizes of weather vanes, depicting pigs, exotic animals, cows, ships, eagles, angels, the last name or address of the owner and the ever-popular rooster. Weather vanes are typically manufactured from copper or wrought iron, though cheaper versions made from lighter metals are available too.