Circumhorizontal arc over Singapore
© Via Facebook/All Singapore Stuff
Singapore witnessed a similar sky phenomenon two years ago, although experts from the Meteorological Service Singapore have claimed that the unusual sight was an iridescent cloud.

A unique rainbow-like celestial phenomenon has been spotted in Singapore. A Facebook community called All Singapore Stuff posted a video showing a mesmerizing iridescent cloud shimmering in the sky.

While this unusual sight is often referred to as "fire rainbow", this marvelous optical phenomenon has nothing to do with either fire or rainbows and is actually called a circumhorizontal arc. This arc appears in the sky when sunlight strikes through ice crystals suspended in high-altitude cirrus or cirrostratus clouds. Singaporeans who saw this phenomenon should consider themselves lucky as the circumhorizontal arc does not normally appear in this area of our planet due to the geographical proximity to the equator.