This is a very interesting website if you like “unusual” clouds.
http://www.atoptics.co.uk/droplets/iridim0.htm
The above link came from www.spaceweather.com
Space Weather has some pictures today of irridescent clouds taken June 18th in Missouri at the Heart of America Star Party.
http://www.spaceweather.com/swpod2007/20jun07/Martinez3.jpg
http://www.spaceweather.com/swpod2007/20jun07/Martinez1.jpg
In a time not so long ago the appearance of the skies I witnessed was more predictable. Is that a good way to describe it?