Weather explained: How are rainbows created?

It's that time of the year when rainbows most commonly colour our sky, but how are they created?

Rainbows are an optical illusion and are formed when sunlight is scattered through raindrops. Given April is the month of sunshine and showers, the weather creates the perfect recipe for rainbows.

A rainbow is simply a spectrum of light. They are a result of both reflection and refraction. Both involve a change in the wavelength's direction; reflection is when it "bounces back", while refraction is when it is "bent".

When sunlight hits the water droplet, it is refracted, then reflected, each at a different angle and wavelength, which is what forms the varying colours in the observer's eye.

For rainbows to be visible, the position of the sun and the raindrops relative to the observer need to be just right. This includes the sun being at an angle of, or less than, 42 degrees in the sky, the sun behind the observer and water droplets in front of the observer.

The water droplets can be from precipitation, mist, fog, sea spray or even waterfalls. So if you spot any, don't forget to send us in your shots to our dedicated uploader to feature.