Fire rainbows are the rarest of all naturally occurring atmospheric phenomena. For a fire rainbow to occur, cirrus clouds must be 20,000 feet in the air with the precise amount of ice crystals, and the sun must hit the clouds at 58 degrees. ~Poppet
Colourful light pillars often appear in winter when snow or ice crystals reflect light from a strong source like the sun or moon. Aided by extreme cold, light pillars appear when light bounces off the surface of flat ice crystals floating relatively close to the ground.