Halo also known as sun dogs usually appear but not always, when the sun is fairly low, but in this case it appears during broad daylight. This phenomenon occurs when the atmosphere is filled with ice crystals forming cirrus cloud, in short when the light passes through the light reflected and refracted. Here are the picture taken during mid day. For further detail check this websitehttp://www.komonews.com/weather/faq/4308372.html
