system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do clouds tend to clump together in the sky, rather than the water vapor just being spread out equally over the air?
gpt
Clouds tend to form at the top of updrafts, as the upward-moving air expands and cools, prompting it to dump its water as a mist which forms the clouds.

Obviously, the whole sky cannot be one big updraft, as air must also be moving downwards in order to take the place of the air moving upwards. This forms many different cloud shapes, including the traditional convection cell hex grid - if you look carefully you will sometimes be able to make out a hexagonal grid arrangement where clouds are at the center of each hexagon. This is because circular convection cells form and when they come together the circles form a hexagonal grid.