How the sun is the main factor behind clouds and rain?
We know that due to heat from the sun shines down on the earth the water of oceans, rivers, lakes, ponds, etc gets evaporated so, the air along with the water vapour, gets warm and rises up.
As it goes higher up in the sky, it cools down.
The water vapour condenses to form tiny drops of water. Millions and millions of these droplets together form a cloud.
When the clouds pass through cooler air, they get further cooled. The water drops becomes bigger and heavier. When they become very heavy, they fall to the ground as rain. So, from here we understand that the sun is the main factor in influencing weather by giving heat to form clouds and pour rain drops.
Most of the water that falls on land goes back into the oceans, rivers, lakes, ponds, etc. Again at a certain altitude the vapours changes into clouds and clouds into rain.
This goes on repeating. This repeated change of water to water vapour, and then back to water, is called the water cycle.