An iridescent cloud phenomenon was witnessed in Costa Rican skies by awestruck residents on Tuesday afternoon.

The luminous cloud spectacle, which coincidentally occurred on the country's Independence Day, lit the skies at different cities including Parrita, San Jose, Pavas, Hatillo and Escazu.

As people were stunned, many posted photos and videos of the astonishing cloud formation with some even claiming it was a sign of "end of times".

Joey Petit, a resident, told ABC News that his family was at the playground for the Independence Day festival in Escazu when his son, 11-year-old Ariel Joseph first saw the huge rainbow-colored cloud.

"He immediately grabbed the camera and started taking video and photos," he said. "We were just so amazed. We had no idea what it was and we'd never seen anything like it."

"It's the most beautiful thing I've ever seen," Ariel Joseph said in the video.

"Look at the sky, it's like a sign of God," another Escazu resident Jessie Montealegre said. "It's like the Lord is gonna come through these clouds any moment."

As various theories such as UFO and end of the world flood the social media, experts explained this is an effect of a rare weather phenomenon called "cloud iridescence".

According to Costa Rica's National Meterological Institute meteorologist Eladio Solano, this cloud sighting occurs when the light of the sun hits water droplets and ice crystals in the cloud.

Just last month, a similar cloud phenomenon occurred in the skies of South Carolina.

Dubbed as the "fire rainbow", the rare sky spectacle stunned witnesses who were also able to take lots of photos and videos.

This is "one of many optical phenomena that exists when the sunlight interacts with various types of clouds -- especially those in the highest level of the atmosphere, which are largely made of ice crystals," a rep for the National Weather Service said. "This really represent nature's more beautiful color shows."