It's a rainbow, caused by rain and the moonlight! Never knew about this, more details are here I can't be the only one amazed by this can I? Everyone I told have looked at me with a "You have know life" type of look...
Can also be caused by anything that projects water into the air. One of our state parks has a moon-bow once or twice a year where the water falls over a dam.
I have seen a rainbow caused by a huge waterfall, but not a moonbow! Sounds wonderful. Will look out for it! Thanks for sharing!
It's easier to see them if you live in certain parts of the world, althoug a kind of moonbow is when you see a full circle rainbow around the moon.. you guys ever noticed that?