A fog bow is a similar phenomenon to a rainbow; however, as its name suggests, it appears as a bow in fog rather than rain. 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.

AKB48 perform during the MTV Video Music Aid Japan at Makuhari Messe on June 25, 2011 in Chiba, Japan. (Photo by Koki Nagahama/Getty Images)

The rising sun penetrates early morning mist and begins to burn off the first frost of winter in the Cheshire countryside at dawn on 24 October, 2007, Knutsford, England. (Photo by Christopher Furlong/Getty Images)

A traveller washes his horse in the River Eden in preparation for selling at the Appleby Horse Fair on June 3, 2011 in Appleby, England. Appleby Horse Fair has existed under the protection of a charter granted by James II since 1685. It is one of the key gathering points for the Romany, gypsy and traveling community. Appleby Horse Fair is attended by about 5,000 travelers who come to buy and sell horses. The animals are washed and groomed before being ridden at high speed along the “mad mile” for the viewing of potential buyers. (Photo by Christopher Furlong/Getty Images)

A Thai security guard stands by a wall of sandbags in front of a factory at the Bangchan Industrial Estate area on the outskirts of the capitol city November 8, 2011 in Bangkok, Thailand. Over seven major industrial parks in Bangkok and, thousands of factories have been closed in the central Thai province of Ayutthaya and Nonthaburi with millions of tons of rice damaged. Across the country, the flooding which is now in its third month has affected 25 of Thailand's 64 provinces. Thailand is experiencing the worst flooding in over 50 years which has affected more than nine million people. Over 400 people have died in flood-related incidents since late July according to the Department of Disaster Prevention and Mitigation. (Photo by Paula Bronstein /Getty Images)