When I took the dogs out for their first run this morning, I thought I heard an airplane going over. I didn’t see a plane, but I was astonished at the sight of a rainbow in the clouds overhead. The sun is out of the bottom frame in the image above. I can’t remember seeing a rainbow arc away from the sun until today. Click on the image to enlarge.
Update: I uploaded the image to SpaceWeather.com and found out that this is a circumzenithal arc:
The circumzenithal arc, CZA, is the most beautiful of all the halos. The first sighting is always a surprise, an ethereal rainbow fled from its watery origins and wrapped improbably about the zenith. It is often described as an “upside down rainbow” by first timers. Someone also charmingly likened it to “a grin in the sky”.
Look straight up near to the zenith when the sun is fairly low and especially if sundogs are visible. The center of the bow always sunwards and red is on the outside.