From cloud, rain and snow fall. Water is critical for life here as we know it. We drink it, shower or bathe in it, swim in it, boat on it, use it on our plants. In winter, when snow piles high, we build snowmen and sled or ski on it. We depend on clouds to replenish the water we use.
Warm air is capable of holding more water vapor than cold air.
When air rises as in storms, ahead of fronts or when forced over mountains, it cools and becomes less able to hold water in vapor form. The vapor condenses into droplets, forming clouds. As it continues to rise, the drops grow in number and size. When the drops get sufficiently large and heavy, they begin to fall through the rising air. They may collide with rising droplets and increase in size.