These are called “moonbows” and they appear in only a few places on Earth.
The rainbow is an optical and meteorological phenomenon that is manifested by the appearance in the sky of a spectrum in the form of a colorful semi-circle when sunlight is reflected in the water droplets from the atmosphere.
But what is a “moonbow”?
The explanation is that the moonlight passes through mist or water vapors. They take place when moonbeams hit water droplets in the atmosphere.
The last appearance of a “moonbow” was in Yosemite National Park, USA. Park officials were able to record this phenomenon and the film has already been viewed by people around the world.
Moonbows are best viewed near large waterfalls. They occur when the moon is full or nearly full, and low in the sky.