A rainbow cloud can occur because of something called cloud iridescence. It usually happens in altocumulus, cirrocumulus, lenticular and cirrus clouds. Iridescent clouds happen because of diffraction – a phenomenon that occurs when small water droplets or small ice crystals scatter the sun's light.

May 03rd: Iron Man 3. May 10th: The Great Gatsby. May 17th: Star Trek Into Darkness
May 24th: The Hangover Part III, Fast and Furious Six and Epic. May 31st: After Earth
and: Now You See Me. June 07th: The Internship. June 12th: This is the End
June 14th: Man of Steel. June 21st: Monsters Univer...