But the clouds know how to do it, and that is the important thing. Clouds just keep circling the earth around and around. There is not much else to do. Water vapor gets together in a cloud. When it is big enough to be called a drop, it does.
Humidity is the experience of looking for air and finding water.
Rain is often known as soft water, oppositely known as hail. Rain is saved up in cloud banks. One horsepower is the amount of energy it takes to drag a horse 500 feet in one second. You can listen to thunder after lightening and tell how close you came to getting hit. If you don't hear it you got hit, so never mind.