However, the most common instrument used is known as an anemometer . It consists of three cups on arms that can rotate measuring wind speeds based on rate of rotations and a vane which indicates the wind direction. Flexible trees such as the weeping willow is good for lighter wind conditions whilst trees with stronger, less flexible branches sway during moderate to strong winds. Once wind reaches the strong to gale force category, damage to trees begin to occur such as broken twigs, branches and removal of leaves. The Beaufort scale incorporates these measurement techniques and other effects into certain ranges of wind strength estimates.
Wind can also create sound.
Wind passing around an object causes vibrations of that object that in turn creates a sound, normally a hissing or howling sound. We tend to perceive wind strengths based on certain sounds but mainly because we have really associated these sounds with the wind effects on objects. The movement of fast moving low clouds normally indicates the approximate direction of the wind. Fog also will move in the direction of the wind. Wind can raise dust and other light objects and therefore following, this movement is yet another technique that can help you estimate the strength and direction of the wind.