The short answer

Wind is the result of variations in air pressure which is impacted by differences in temperature (among other factors). In high pressure systems (cold spots), air molecules sink down and blow air away which creates wind. In low pressure systems (hot spots), these molecules rise which draws air in from other spots and creates wind.

The long answer

Wind is caused by the movement of air (duh, you probably knew that). The movement of air is the result of changes in air pressure (also known as atmospheric pressure) which in turn is caused by variations in temperature. What does temperature have to do with air pressure you might ask?

The gases that comprise what we call "air" are made up of molecules that react differently to how hot or cold it is. When the temperature is hot, molecules do three things: move more quickly, spread out, and rise up. Since the molecules are rising up, their weight isn't pressing down on Earth as much, and this causes low air pressure. Conversely, when it is cold, the molecules slow down, get closer together, and sink. This downward weight results in high air pressure.

The earth's surface is made up of different types of land and water, which absorb and release heat at different rates. This causes the air above these surfaces to heat up or cool down, creating temperature differences and resulting in changes in air pressure.

In low pressure systems, cool air rushes in to where the hot air is rising which creates wind. Vice versa, in high pressure systems, the air gets pushed down and blows away from the area. There you have it: wind!

Sources

NOAA SciJinks. (2020). Why Does the Wind Blow? Retrieved December 7, 2022, from https://www.youtube.com/watch?v=-s7zOubwXmc.

University Corporation for Atmospheric Research. (n.d.). The Highs and Lows of Air Pressure. Center for Science Education. Retrieved December 7, 2022, from https://scied.ucar.edu/learning-zone/how-weather-works/highs-and-lows-air-pressure