RRI.CO.ID, Jakarta - The sky has its own remarkable way of pleasing the eye through various optical phenomena. Some of the most beautiful sights we often witness include sunrises and sunsets, rainbows, and clouds in a wide range of shapes.

But did you know that clouds can also create a rainbow-like optical phenomenon? This is known as cloud iridescence, often referred to as a “rainbow cloud.” However, it is distinct from an actual rainbow.

This phenomenon occurs when clouds appear to display a spectrum of colors. Unlike a true rainbow, the colors do not form a perfect arc, but instead appear as soft, scattered hues across part or even the entire cloud.

According to the Indonesian Agency for Meteorological, Climatological and Geophysics (BMKG), cloud iridescence forms when sunlight or moonlight is diffracted by tiny water droplets or ice crystals within clouds, producing delicate, shimmering color gradients.

This phenomenon typically appears in thin, high-altitude clouds such as altocumulus, cirrocumulus, or cirrus. It is more commonly seen in the morning or late afternoon, when the sun is positioned lower in the sky.

Because it requires very specific atmospheric conditions, particularly uniform particle sizes within the clouds, it does not occur frequently. In addition, its appearance can change rapidly, making it visible only for a short period of time.

Despite its brief nature, cloud iridescence often draws public attention. Many people quickly capture the moment due to its unusual and striking beauty.

The phenomenon recently gained attention when it appeared over Gading Serpong, Tangerang, Banten, in February 2026. At the time, the sky was adorned with soft rainbow-like hues spread across thin clouds, attracting residents and quickly going viral on social media.

While cloud iridescence poses no danger and is not associated with extreme weather, it highlights the complexity of the atmosphere and the fascinating way light interacts with tiny particles in the air.