What is the primary cause of wind?

The primary cause of wind is pressure imbalances in the atmosphere. When there is a difference in atmospheric pressure between two areas, the air moves from the region of higher pressure to the region of lower pressure in an attempt to achieve equilibrium. This movement of air is what we experience as wind.

While heat from the sun does play a significant role in the process by influencing temperature gradients and thus contributing to pressure differences, it is the pressure imbalances that directly cause the wind to flow. Similarly, while Earth's rotation can affect wind patterns through the Coriolis effect, it is not the initial cause of the wind's movement. Changes in humidity can also affect weather patterns and local winds but do not serve as the primary driving force behind the generation of wind itself. Ultimately, it is the pressure variations that create the conditions necessary for wind to develop.