For many photographers, taking a picture of the elusive double rainbow is a rare and unexpected treat. Not only do you have to be at the right place at the right time, you need to have your camera on hand so that you don't miss nature's colorful show. As photographer Craig Bill stated about his photo, above, “By the time we had almost seen the first canyon edge, ambient storm clouds started to shed rain. If you look closely, you can see the first drops of rain on the foreground rocks. Afraid of equipment damage, I advised that we start back toward camp before nature taught us a lesson. Not ten steps into the retreat, my safari companion yelled out, ‘Look! a double rainbow!' I scrambled to get my camera together. I climbed up a rock and started shooting as many exposures as possible before the elusive event faded. That was the brightest rainbow I have ever seen – and to see it arching over Toroweap, Grand Canyon is one of the luckiest and most exciting experiences I have had with photography!”
In a double rainbow, two rainbows are seen in the sky at the same time. The second arc, outside the primary arc, has the order of colors reversed. That means instead of red, orange, yellow, green, blue, indigo, violet, the outer edge starts with violet followed by indigo, blue, green, yellow, orange and red.
According to the National Center for Atmospheric Research, this natural phenomenon occurs when a part of a ray of sunlight that enters inside a raindrop is reflected for a second time in the droplet before exiting it. Essentially, you're looking at a second reflection. The outer edge is fainter than the primary because more light escapes from two reflections compared to one and because the rainbow itself is spread over a larger area of the sky.
Even more rare than the double rainbow is the twinned rainbow, or two rainbow arcs split from a single base. In this case, the colors don't reverse, they appear in the same order as the primary one.
Now, let's take a look at 21 glorious photos of double rainbows spotted all around the world.