Fog bow

A fog bow, sometimes called a white rainbow,[1] is a similar phenomenon to a rainbow; however, as its name suggests, it appears as a bow in fog rather than rain.

[2] Because of the very small size of water droplets that cause fog—smaller than 0.05 millimeters (0.0020 in)—the fog bow has only very weak colors, with a red outer edge and bluish inner edge.

[3] The colors fade due to being smeared out by the diffraction effect of the smaller droplets.

Along with its larger angular size, this lack of color is a feature of a fog bow that distinguishes it from a glory, which has multiple pale-colored rings caused by diffraction.

Mariners sometimes call fog bows sea-dogs.