Lunar halo December 22, 2012 – Photo courtesy of Andrew Bentz

Southeast Arkansas residents experienced Saturday night what many said was the largest halo around the moon they had ever seen. Social media sites were buzzing about it, many sharing photos and discussing what kind of weather change is in store for us. The photo on the left is the lunar halo as seen from Monticello Saturday night. The photo was provided by Andrew Benz of Monticello.

A lunar halo is caused by the refraction, reflection, and dispersion of light through ice particles suspended within thin, wispy, high altitude cirrus or cirrostratus clouds. As light passes through these hexagon-shaped ice crystals, it is bent at a 22 degree angle, creating a halo 22 degrees in radius (or 44 degrees in diameter). A double halo, sometimes with spokes, may be seen on rare occasions when light reflects off water or ice. The prism effect of light passing through these six-sided ice crystals separates the light into its various colors, resulting in a halo tinged with very pale rainbow colors with red on the inside and blue on the outside. The phenomenon of a lunar halo is similar to a rainbow produced by sunlight and rain falling between your eye and the sun, according to the Farmer’s Almanac.

Weather lore says a lunar halo is the precursor of impending unsettled weather, especially during the winter months.