The stronger the wind speed (generally, a surface wind of 20 knots or higher is required for significant turbulence), the rougher the terrain and the more unstable the air, the greater will be the turbulence. Of these factors that affect the formation of turbulence, stability is the most important.

Technically, wind itself does not cause turbulence; rather, turbulence is caused by disruptions in the wind's flow. Think of wind as a river; a steady, fast-moving river is smooth, but it becomes "turbulent" when it hits rocks or changes speed suddenly. In aviation, this occurs in four main ways. First is Mechanical Turbulence, caused when wind hits physical objects like mountains or tall buildings and "tumbles" over the other side in erratic eddies. Second is Wind Shear, which happens at the boundary where two air masses are moving at different speeds or directions, creating a churning effect. Third is Thermal Turbulence, where hot air rises off the ground in "pockets," causing a bumpy ride as the plane moves between high and low pressure. Finally, Jet Streams create turbulence along their edges where the high-speed "river of air" meets slower air. So, while high wind speeds can make these disruptions more violent, it is the change in wind velocity or direction that actually makes your coffee spill.