How does rain form in clouds??

Answer 1

In a sense,it is rain in plain sight,its just that the particles of moisture hanging on to tiny bit of dust particle have remain buoyant due to there small size.
But rain will come if you have enough of those little guys up there bump into each other,so that gravity can do the rest.

Another way that you can get all that moisture out of those clouds is them going over mountainous areas.for eg;The Pacific north west receives heavy rainfall due to their mountainous back drop,by clouds rising over the mountains cooling and then condenses into rain,or relief rainfall as it is called.

Answer 2

Small water particles aggregating around a nucleus, which could be a speck of dust.