One way to think about wind is that it is simply “air” in motion. The formation of wind occurs when suns heats up air in part of the atmosphere, while another part of the atmosphere may be much colder. As air warms, it expands causing it to rise and replace colder air above it. As air expands, pressure decreases compared with colder regions where pressure is higher. Air flows from high pressure to low pressure and this is what causes wind to blow!