This iridescent cloud was seen before a summer thunderstorm in Bangkok on Thursday.

The recipe for these dreamy halos of multicoloured mist floating over ominous storms is simple.

Iridescent clouds, also known as "fire rainbows" or "rainbow clouds", occur when sunlight diffracts from water droplets in the atmosphere.

They usually accompany thun-derstorms, often appearing in the late afternoon on very hot and humid days.

This is because most rainbow clouds form on top of cumulus clouds - the fluffy cotton-ball-shaped clouds we often see in children's drawings.

But although the ingredients seem simple, these clouds are not spotted often, and are even less frequently photographed.