One of the rarest phenomenon, conditions have to be perfect to see a Fire Rainbow or a circumhorizontal arc. Don Spear was lucky to see and photograph one recently.
The sun needs to be very high in the sky, so around the summer solstice is ideal. The sun needs to hit the clouds at exactly 58 degrees. Rather than being on fire, though, it is cold as ice.
Thanks to Don for allowing me to share his photo with you here. To see a photo of another unusual event caused by light refraction, here's a link to see a Fog Bow. http://www.mendonomasightings.com/2012/10/29/fog-bow-as-photographed-by-peggy-berryhill/