A ring or circle of light around the sun or moon is called a halo by scientists. The most recently spotted Halo was on 25th November 2012. Halos are the clouds contain millions of tiny ice crystals. The halos you see are caused by both refraction, or splitting of light, and also by reflection, or glints of light from these ice crystals. The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear. The night before Hurricane Sandy made landfall on the U.S. mainland on October 29, 2012, for example, many on the U.S. East Coast saw a lunar halo. The night of the landfall itself, as clouds from Sandy covered the U.S. East, many in the U.S. Midwest and West saw a halo. We do not know if Sandy was responsible for these halos, but in fact lunar and solar halos are associated with nearby storms.
Solar and Lunar halos are pretty common. But people who spots it feel like something natural disaster is going happened soon. The bottom line is that Halos around the sun or moon happen when high, thin cirrus clouds are drifting high above your head. Tiny ice crystals in Earth’s atmosphere cause the halos. They do this by refracting and reflecting the light. Lunar halos are signs that storms are nearby.