What is a Weathervane?

A weathervane is an instrument for showing the direction of the wind. They are typically used as an architectural ornament to the highest point of a building. Although partly functional, weather vanes are generally decorative, featuring an ornamental design with letters indicating the points of the compass. Common weathervane designs include roosters, eagles, horses, blue heron, boats and ships, arrows, and more.

The design of a weathervane is such that the weight is unevenly divided on a vertical shaft so the vane can spin freely in the slightest breeze. The side with the larger surface area is blown away from the wind direction. In other words, the arrow, or front of the weathervane, points into the wind, not with the wind. If the vane were designed with the weight evenly divided on the vertical shaft, the vane could not function properly.

Nowadays, weathervanes take on on many fancy and unique designs that may not always tell the real direction of the wind. These designs are more decorative and were not intended to be accurate, but ornamental.

In order to receive an accurate wind reading, the weathervane must be located well above the ground, away from trees, buildings, and other objects that hinder and interfere with true wind direction. As stated above, however, most weathervanes today are used purely as a decorative focal point, and are installed where the owner chooses will look the most prominent, not where it will get the best wind reading.