Despite looking really weightless, clouds are actually heavy.
Even small, fluffy clouds are heavy.
The water in small clouds can weigh more than million pounds, which is more than 500 cars.
Clouds are able to float in the air because water vapor in the cloud is less dense than water in a liquid state.
Furthermore, clouds are usually formed in air that is moving upward.
So, as long as the water is in the form of tiny droplets, it floats in the warm up-currents.
It’s only when the air cools that the mist condenses into large drops and the downward pull of gravity trumps the upward push of rising air.
Then rain falls.