What primarily causes wind currents?

Wind currents are primarily caused by horizontal differences in air pressure. When air pressure varies across a region, the atmosphere seeks to equalize this difference, leading to the movement of air from areas of high pressure to areas of low pressure. This movement is what we perceive as wind.

Factors such as temperature variations and geographical features can significantly influence these pressure differences. For example, the sun heats the earth unevenly due to variations in surface color and texture, leading to differing temperatures and subsequently to differences in air pressure, which ultimately drive the wind currents.

Humidity levels can affect air density and pressure but are generally secondary to the direct impact of pressure differences. In summary, while temperature variations and local geographical features play a critical role in the formation of wind currents, it is the horizontal differences in air pressure that are the fundamental cause of wind movement.