We’ve all witnessed a rainbow - but have you ever seen a moonbow? Where to spot the rare phenomenon...

Have you ever seen a moonbow? 

If you have, you’ve witnessed an extraordinary phenomenon. It's not the ring we sometimes see around the moon. Moonbows are lunar rainbows, on the horizon, and are super rare because the conditions have to be just right. 

For a moonbow to appear, the moon has to be full, bright, and low in the sky. The sky needs to be very dark and of course there must be rain falling, opposite the moon. You’ll need to get up early to spot one. Because the sky is still light at moonrise, moonbows are more likely at moonset, two or three hours before sunrise. A lunar rainbow appears whiter than a solar rainbow but it’s full spectrum of color will appear on film if you’re lucky enough to catch one.

Moonbows are nothing new. Aristotle’s Meteorology, circa 350 BC mentions them. There are a few spots on the planet that are prime for moonbows and many of them cheat a bit with the aid of waterfalls. These are categorized as spray moonbows. To spot one, head for Yosemite National Park in California, Cumberland Falls in Kentucky, Victoria Falls in Africa or to the border of Zambia and Zimbabwe.