how do rain appears?

Answer 1

rain, precipitation in liquid form. It consists of drops of water falling from clouds; if the drops are very small, they are collectively termed drizzle. Rain plays a key role in the hydrologic, or water, cycle in which moisture from the oceans evaporates, condenses into clouds, precipitates back to earth, and eventually returns to the ocean via runoff into streams and rivers to begin the cycle again.
Formation of Raindrops

Clouds contain huge numbers of tiny droplets of moisture. Raindrops are formed when these tiny droplets are enlarged, first by moisture from the surrounding air condensing on them and then by coalescing with other droplets during their descent. Raindrops vary in size from about 0.02 in. (0.5 mm) to as much as 0.33 in. (8 mm) in thunderstorms. From the time they leave the bottom of the cloud, evaporation takes place and, if the cloud is high, the air warm and dry, and the raindrops small, so that they fall slowly, they may evaporate completely before they reach the earth. If they do so, the drops are called virga.

Answer 2

Rain occurs when specific weather conditions exist in the upper atmosphere(s), and super saturated clouds either start releasing water droplets, or get "seeded" by dust particles in the air.

Answer 3

Rainbows do no longer constantly look in basic terms after rain. you may create a rainbow each time with a backyard hose. After it rains, in spite of the shown fact that, there's a bigger danger of there being water droplets interior the air that are sufficiently small to create the refraction consequence that we call a rainbow.

Answer 4

Short answer. Airborne moisture makes clouds and when those clouds move into cooler conditions it rains.

Long answer. Google Hydrological Cycle. There is a lot of stuff available.