Weather explained: How do rainbows form?

Question: How does a rainbow form?

Answer:

As raindrops pass through rays of light, a rainbow's colours become visible despite being white light from the Sun.

Each colour has a different wavelength, as light hits raindrops the sunlight is refracted into the spectral colours. The light we see reaches our eyes at a 42-degree angle, forming a circle, and from our perspective the classic rainbow shape.

Video explainer: