What causes rainbows to form after rain?

Rainbows form when sunlight passes through water droplets in the atmosphere, bending and splitting into its component colours. This process, known as refraction, separates light into a spectrum of colours—red, orange, yellow, green, blue, indigo, and violet. The light reflects inside the droplets and exits at a specific angle, creating the arc-shaped rainbow. Rainbows are most visible when the Sun is low in the sky, and the viewer is positioned with their back to it.