I submitted this photo earlier in the Collegial Thread, but the more I look at it, the more I like it, not so much for the rainbow itself, but for the line of demarcation it makes in the sky.
It's a little late in the day. You're looking south, so east is to your left as you look at the photo. The sun is setting to your right in the west. The setting sun hits that rainbow and floods the sky with color like a spilled paint can.
It;s kind of neat.
Steve Thomas