Fun Facts about Rainbows

Rainbows can only appear directly opposite from the sun. Where, and even if, a rainbow appears is influenced by where the viewer is in relationship to the sun.

Rainbows have no set physical location. A person who appears to be standing at the end of a rainbow from another person's perspective won't see the rainbow in the same place, but will instead see another rainbow in a different location, opposite the sun. The top of the arc is always centered on the viewer's head.

Sometimes a so-called "double rainbow" forms, with a more faint rainbow appearing on top of the main one. This occurs when the light is reflected twice in each raindrop, instead of just once. The double reflection causes the second rainbow to be inverted, so in a double rainbow, the colors in the secondary rainbow appearin the reverse order compared to the primary, or darker rainbow.

The sky beneath a rainbow appears brighter than the sky above it. Light rays are refracted into the area inside the arch, causing that area to appear brighter. The area outside the rainbow appears darker by contrast.

Rainbows appear to be a semi-circle because the horizon interferes. In order to see the full circle of the rainbow, you would have to look down on it with the sun behind you.