Double Rainbow
A double rainbow is a natural phenomenon where the raindrops refracts light that creates a dispersion which creates a normal rainbow, but on top of that if a specific moment at a specific time the raindrops meets a certain condition then another rainbow shows up out of the blue.
A double rainbow occurs when the light is reflected twice in the drop. It means you can see two different reflections, coming from different angles . This leads to something that is actually really cool instead of seeing red at the top and blue at the bottom like a regular ho-hum rainbow, the secondary rainbow (which is higher and lighter in color than the primary) has the colors reversed.
'How often can you come across a double rainbow?'Is the question, welp it is not that rare at all actually, There is a chance that if you had ever seen a rainbow, one of them is probably a double, triple or even quadruple rainbow.
It is actually where to see it, it is always different every time though, so it is not rare but hard to come across.
This refraction isn't that rare also so every rainbow has a change for another one to come out of the blue.