Why do we see rainbows?

Rainbows occur when sunlight passes through water droplets in the atmosphere. The light is refracted, or bent, as it enters the droplet, then reflected inside the droplet, and refracted again as it exits. This process separates the light into its component colours—red, orange, yellow, green, blue, indigo, and violet—forming a circular arc. Rainbows are always seen opposite the Sun, and their appearance depends on the angle of the light and the observer’s position. Double rainbows and supernumerary rainbows can occur under specific conditions.