Cirrus clouds look like rainbows. Those who look from the ground see the cloud in the form of a rainbow as the sun makes a minimum angle of 58 degrees with the horizon and the ray entering from one side of the hexagonal cirrus crystals is refracted. It is a rare weather phenomenon.

Rays of different wavelengths are refracted at different angles when passed through a prism (once entering the prism and once leaving the prism). Thus, white light decomposes into different colored lights that make up it. The angle of refraction is largest for red color and smallest for purple color.

Rarely occurring "rainbow clouds" have been spotted over Lake Lugu in southwestern China's Sichuan province.

The clouds adorning the sky with colorful lights amazed the viewers. While the clouds created a visual feast, the viewers were fascinated.