Watch: Rare ‘rainbow clouds’ light up the sky, leave viewers stunned

Screengrabs from video Instagrammed by @explorewithjoshua

People in parts of Scotland last week got to witness a rare, natural light show with shimmering rainbow clouds in the sky. Stunning footage that has gone viral online shows iridescent clouds in shades of pink, purple and orange lighting up the sky.

According to Newsweek, the rainbow clouds were seen above Nairn Beach shortly before sunrise on December 24.

Joshua Earle, a 29-year-old local photographer, captured the rare phenomenon and shared it on Instagram for the world to witness. “It was incredible on that morning. The horizon was full of these clouds and was more vibrant than before. Literally shimmering rainbows in the clouds,” he told Newsweek.

View this post on Instagram

A post shared by Joshua Earle | Adventure Travel (@explorewithjoshua)

“This strange phenomenon is caused by high arctic clouds that contain tiny ice crystals that refract the sunlight. It’s worth keeping an eye out at sunrise and sunset this weekend if you’re in the UK. You might just spot a rainbow cloud!” he explained.

"This was the first time I've seen these clouds but, funnily enough, they have appeared three or four times in the week leading up to the 24th," the photographer told Newsweek.

Polar stratospheric clouds (PSCs), also known as nacreous clouds, are visually stunning cloud formations that occur in the winter polar stratosphere in extremely cold temperatures. The iridescence is caused by diffraction and interference of sunlight passing through the cloud's tiny ice crystals.