Every once and a while an email shows up in my inbox with a picture of the "extremely rare fire rainbow!", with breathtaking text about how incredible and rare a phenomena it is.
Of course if it is on the internet it must be true.
(I hope you answered "no".)
((And yes, I get the irony.))
I saw a "fire rainbow", more accurately known as a circumhorizon arc, out my office window yesterday.
As you can learn at the wonderful Atmospheric Optics website, the phenomena isn't all that rare at all, and is visible in my neck of the woods multiple times throughout the summer.
And it isn't a rainbow. And it has nothing to do with fire. It is the result of light refracting through ice, with the crystals acting like prisms.
The sun needs to be high in the sky, which where I live means late spring, through summer, and into early fall. And you need those ice crystals, in the form of thin clouds, to create the display.
So when you are out and about this summer look up. What you see may not be rare, but it is still incredible.