We may not be as excited about a double rainbow as this guy, but the picture above is still quite impressive. Captured by Associated Press photographer Steve Vaughn on May 1 in Hamilton, Ohio, the image shows both a lightning strike and a double rainbow.
According to the National Center for Atmospheric Research, a double rainbow happens when the ray of light that causes a single rainbow is reflected twice within raindrops and exits at a greater angle than a single rainbow. The Straight Dope explains:
Luckily for Vaughn, he was able to witness both rainbows as a lightning bolt pierced the sky. For more double rainbow action, look at these double bows above London, New York and Washington, D.C.. Be sure to check out Jimmy Kimmel's interview with the "Double Rainbow Guy," whose unrivaled excitement for a double rainbow garnered him tens of millions of YouTube views.
Because the twice-reflected light has had two chances to be transmitted out the back of the raindrop rather than reflected back toward the observer, the secondary bow is much fainter than the primary and frequently cannot be seen at all; it's typical for a secondary rainbow to be visible only at certain points along the arc.