As the sun shines on Earth the water contained in the oceans, lakes and soil heats up and evaporates and this water vapor goes into the atmosphere. As it rises into the sky the air gets cooler and the vapor condenses to form tiny drops that all togetherbecome clouds. Inside the cloud the droplets move around crashing into one another creating bigger and heavier drops. At this point they are too heavy to stay in the sky and fall onto the ground as rain.
No Tears! We often see raindrops pictured as teardrops, Not true! When falling the smaller raindrops are spherical while the bigger, heavier ones are flatter, almost like a hamburger bun, the biggest ones look a lot like parachutes.
All raindrops are not pure H₂O, they can contain tiny solids or sometimes liquids. That is why sometimes rain is acidic or contains bits of sand, maybe from the Sahara desert! You can see the dust on cars or other places after it dries.
All the rain in the world: the atmosphere contains water vapor, if all the water in the atmosphere should fall at the same time all over the world as rain the whole planet would get about an inch (2.5cm)of it .
Feeling sticky? Sometimes the air around us contains a lot of water vapor, you feel sweaty and sticky because your sweat can't evaporate easily and stays on your skin.
World records. The rainiest place on Earth is in South America in Llorò Colombia. 13.30 meters of rain fall on average every year here, that's as high as a four storey building! The driest place on earth is always in South America, in Aica, Chile where for the last 50 years the average rainfall is only 7 mm a year.