A rare rainbow cloud formation spotted over parts of Indonesia has gone viral on social media, with videos showing glowing clouds in shades of pink, green and blue leaving users stunned and searching for what caused the unusual sky phenomenon.

The clips, reportedly filmed over Bekasi and Bogor Regencies, quickly gained attention online after users shared footage of shimmering clouds above Jonggol in Bogor.

Many viewers initially believed the visuals were edited because of the unusually bright rainbow-like colours lighting up the sky.

One social media user joked, “Pride month came early for the pride fam,” while another described the scene as “a real rainbow cloud painting the sky like a masterpiece.” Some users questioned the authenticity of the footage, calling it “edited” due to the dramatic colours visible in the clouds.

According to Indonesia’s Meteorology, Climatology, and Geophysics Agency, the viral rainbow cloud effect is a natural atmospheric phenomenon linked to atmospheric optics.

What caused the viral rainbow clouds in Indonesia?

The colourful effect is known as cloud iridescence, often referred to online as “rainbow clouds” or “fire rainbows.” The phenomenon occurs when sunlight passes through tiny water droplets or ice crystals inside thin clouds.

As the sunlight bends through these particles, the light separates into different colours, creating a prism-like glow across the clouds. This interaction produces the bright patches of pink, green, blue and other rainbow shades visible in the viral videos.

Meteorology experts said the phenomenon is not unusual and can appear under the right atmospheric conditions, especially when thin clouds interact directly with sunlight.

The viral videos have continued circulating across social platforms, with many users comparing the glowing clouds to a painted sky or a “fire rainbow” effect.