Question

why do we see rainbow during rain​

Answer 1

Answer: because we look at sky :-p

Explanation:

Answer 2

$\huge{\underline{\underline{\mathbb{\red{ANSWER!}}}}}$

We see rainbows when the sun is behind us and falling rain is in front of us.

When sunlight strikes a falling drop of water it is refracted, changed indirection, by the surface of the water.

The light continues into the drop and is reflected from the back of the drop to the front. When the beam hits the front it is refracted again and emerges from the drop as the color spectrum that we see in a rainbow.

The water drop acts like a prism to seperate the light into its different wave lengths.