Sun Halo Sunrise Over Winter Southern FingerLakes In NYS Stock Photo

These ice crystals are contained in cirrostratus clouds that are located from 3 to 6 miles, in the upper troposphere. The shape and orientation of these crystals affect the appearance of the halo. Reflection and refraction control the shape of the sun halo. Sun halos are generally considered rare and are formed by hexagonal ice crystals refracting light in the sky 22 degrees from the sun. Rain will occur within 24 hours, because the cirrostratus clouds that cause halos usually mean a front is near.