system
Given the following post, respond as if you're commenting on Reddit:
human
What causes gusts of wind?
gpt
Wind is a turbulent flow.  Turbulent flow is characterized by tangles of vortices (think of a ladies hair after pulling curlers from it) going every which way.  The sizes of the vortices range in diameter between the smallest (small and likely smaller than your pinky, but it depends on the mean speed of the wind which supplies the energy to generate the turbulence) to the largest scales defining the space confining the flow (either the boundary layer or perhaps the width of boundaries like the facades of buildings).  Most of what you feel, and where most of the energy is, is in the larger scales.  The vortices are carried in a mean flow and the combined flows, carrying the vortical flow, can hit you in reverse or going forward, left or right, up or down. Hence gusts.  Now ask why vortices and why the cascade of velocity scales.  Turbulence is really interesting.