How to Read a Weathervane
Find a good vantage point. A weathervane is placed at the highest point of a structure, far above the property, or on the top of a fence. Position yourself so you can clearly see the entire weathervane and its directionals. If needed, use a pair of binoculars to get the weathervane within your sights so you can read it when the wind begins to blow.
Understand the instrument's movement. A weathervane is constructed to be balanced on either side of its axis, but to be slightly heavier at the one end of the ornamental piece. This end turns to face the wind when it blows, causing the weathervane to point toward the source of the wind and allowing you to read its direction. Many weathervanes have a wind directional at the bottom, which identifies the direction from which the wind is originating. This part stays fixed and immobile in the breeze.
Watch the direction of the wind. The patterns of weather systems vary depending on your location. Generally, storm systems move from west to east, but there are regional differences, such as in the Gulf Coast and the Southeast, areas that are prone to tropical storms and hurricanes coming from the southeast and southwest; and the East Coast's Atlantic region, where storms can sometimes come from east to west, such as in the case of a nor'easter or a hurricane that has made its way up the coast. The wind's direction indicates where the storm is coming from.
Read the wind direction from the weathervane. As a breeze starts to blow, watch the weathervane spin. With a steady wind, it points to the source of the wind. Then, use the directional markers below to easily determine the source direction (north, south, east or west). For more accurate readings, some weathervanes have additional directional markers outlining more specific bearings, such as northeast or southwest.
Record your findings. Keeping a weather journal and writing down the wind direction at certain points in the day helps you determine if there is a storm system on its way. Tracking wind direction over a longer period of time allows you discover weather trends at certain times of the year.