Scientists would have you believe that wind is caused by things like the sun heating up the atmosphere unequally thus causing pressure differences which are resolved by the movement of large bodies of air. They also cite the rotation of the Earth and things like the jet stream.
This is all myth. Wind is really caused by trees swaying back and forth. If you sit for a long time and really pay attention, you can learn the difference between joyful and melancholy movements. Eventually, you come to realize that they are dancing for each other but always alone.