Sunbow

Sunbow in Oxford UK in July.

Similar to a rainbow but appears in a clear sky, without rain and does not arc to earth.

Also used of a rainbow produced when sunlight shines through spray. the first impression is that of an upside-down rainbow The circumzenithal arc or circumzenith arc (CZA), also called the Bravais' arc, is an optical phenomenon similar in appearance to a rainbow; but it arises from refraction of sunlight through horizontally-oriented ice crystals, generally in cirrus clouds, rather than from raindrops. It forms no more than one-quarter of a circle centered on the zenith and on the same side as the sun. Its colors are from blue on the inside to red on the outside of the arc