The skies over Huntley Meadows Park were amazing around 3:00 (15:00 hrs) yesterday afternoon when a cold front was blowing in. When certain clouds were illuminated by the sun they were transformed into pastel shades of the rainbow. At times there were varying shades of orange, green, aqua, and purple.
I suspected that moisture in the clouds was responsible for the colors, but I had never seen anything like it and did not know what it was called. After searching about on the internet, I learned that this diffraction phenomenon, known as cloud iridescence, is caused by small water droplets or ice crystals individually scattering light. According to Wikipedia, ” If parts of clouds have small droplets or crystals of similar size, their cumulative effect is seen as colors. The cloud must be optically thin, so that most rays encounter only a single droplet. Iridescence is therefore mostly seen at cloud edges or in semi-transparent clouds, and newly forming clouds produce the brightest and most colorful iridescence.”
© Michael Q. Powell. All rights reserved.
Mike Powell 
Wow, Mike, I have never seen anything like this before! Like rainbow clouds. Interesting reading, and amazing images!
Wow! I’ve never seen anything like that. What an amazing sight.
Good photos, Mike! The following Web site is an excellent resource for understanding atmospheric optical phenomena: http://www.atoptics.co.uk/
How fortunate for us all that you spotted this phenomenon — gorgeous sky scape, and one I have never witnessed before.
Well that’s a first Mike! Spectacular!
I never know what I will see when I go out, but I sure wasn’t expecting this. My understanding is that this only happens under certain conditions and the clouds have to be really thin.
Same for me. When I was on Samui, Thailand. Look – http://kmint21.info/samui-rainbow-clouds-25-05/