Rare 'fire rainbow' phenomenon spotted over Singapore

Residents in Singapore were treated to a truly unusual phenomenon, as a so-called fire rainbow lit up the sky in the city-state.

Many people posted stunning photos on social media of the rare spectacle.

NASA says that fire rainbows are actually called circumhorizon arcs, which are created by a unique set of circumstances.

A spokesman said: "The sun must be at least 58 degrees high in a sky where cirrus clouds are present.

"Furthermore, the numerous, flat, hexagonal ice-crystals that compose the cirrus cloud must be aligned horizontally to properly refract sunlight like a single gigantic prism.

"Therefore, circumhorizon arcs are quite unusual to see."