Wind is caused by differences in air pressure in different areas. This air pressure variance is a direct result of uneven heat distribution across the Earth's surface.
The sun heats the equator more effectively than the poles because the equator receives a greater amount of light. This heat causes air to rise, resulting in low-pressure zones. Meanwhile, at the poles, where the air is cool and sinks, low-pressure results. The high-pressure cold air tries to push southward to replace the warm air that has risen in low-pressure zones. The end results are wind and storms, which occur when moisture is added to the equation.