How did Aristotle explain the formation of clouds, rain, and snow?

In the context of hydrologic sciences, Aristotle proposed a theory of precipitation based on the transformation of the four earthly elements. He explained that heat from above converts moisture on Earth into an airy vapor, which rises because it is the nature of heat to ascend.1

As this vapor rises, the heat eventually dissipates. When the heat leaves the vapor, it reverts to water, forming clouds. Aristotle posited that the remaining heat in these clouds is opposed by the cold inherent in the water, which drives the heat away. This cold causes the particles within the cloud to compress, restoring the true nature of the element water. Because water naturally moves downward, it falls from the clouds as rain. In this system, snow is simply the result of clouds that have frozen.1

Aristotle’s framework was rooted in the belief that these elements were not stable and could change into one another, a concept that influenced Western scientific thought for centuries.12