Red rainbows: What are they and how are they caused?

A beautiful red rainbow was spotted in the sky in Finland.

Avie Junno managed to take a photo of the rare sight when he was fishing on a lake in Paijanne Tavastia, which is about 100 miles (160km) north of the country's capital Helsinki.

"It started raining and this rainbow appeared. It was pretty amazing because you could see it from start to end but also it was only red.

"I didn't realise at the time how rare it is to see, but it gave me the creeps so headed back home for the night," Junno said.

Why do they happen?

Rainbows happen when light passes through water in the atmosphere when it is sunny and raining at the same time,

Red rainbows form in the same way as a normal one, but only the red colours show up.

They occur at sunrise or sunset when the Sun is very low in the sky.

When the rays from the Sun are dispersed through the lower atmosphere, the short wavelength colours of blues and greens that you would normally see get scattered, and only the reds and yellows can be seen - which gives the illusion of a red rainbow.

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