Raindrops refract light in a similar way as a prism, thus the colors.

Drawing showing light refraction through a prism and also through a raindrop.

Detailed Description

Just why do rainbows have colors? It is because of the the raindrops refract the light from the sun into a color spectrum. A prism does the same thing.

Details

Image Dimensions: 416 x 169

Location Taken: US