Weather Words: Moonbow

A moonbow, sometimes called a lunar rainbow, to me, is one of the most magical sights in the night sky.

Just like a daytime rainbow, it forms when light is refracted, reflected and dispersed through water droplets in the atmosphere. The difference is that the light source isn’t the sun, but the moon.

Because moonlight is far dimmer than sunlight, moonbows often appear faint, with colors that are subtle or even invisible to the naked eye.

Places like waterfalls or tropical regions, where mist is common, offer some of the best chances of spotting one. Under ideal conditions, a camera’s long exposure can capture the rainbow’s full spectrum of colors, even if our eyes see mostly white or pale arcs.

For stargazers and night sky watchers, catching one is such a treat and can be even more rewarding if you’re able to catch the colors on camera!

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.