On a lovely, perfectly warm Monday afternoon, as I was heading down my back deck stairs, I looked up to see a beautiful smile-shaped rainbow high in the sky, high above the sun. It was stunningly beautiful.
It is an atmospheric phenomena know as a Circumzinithal arc.
You can try sighting one - this was my first and I look-up frequently - when the sun is low in the sky.
A CZA is often accompanied by sun dogs, those small patches of rainbow on either side of the sun.
This CZA appeared alone without sun dogs.