How are ther formed? Consider this special feature of water. It can change form ages(vapor) to a liquid (water) to a solid (ice) and back again. Clouds form when warm water vapor in the vapor cools. It than bacomes tiny drops of water or ice. These droplets of water or ice join togerther in the sky and form clouds. Clouds come in many different shapes and sizes. But there are three main types: cumulus,cirrus and stratus