Sundogs are colored spots of light that develop due to the refraction of light through ice crystals. They are located approximately 22 degrees either left, right, or both, from the sun, depending on where the ice crystals are present. ... Sundogs are also known as mock suns or parhelia, which means "with the sun".

What can cause sun dogs to appear?

Sun dogs are commonly caused by the refraction and scattering of light from plate-shaped hexagonal ice crystals either suspended in high and cold cirrus or cirrostratus clouds, or drifting in freezing moist air at low levels as diamond dust.

What causes a sun dog in the summer?

Sun dogs are caused by a layer of ice crystals between your eyes and the sun which cause a refraction of the light somewhat similar to the process that forms a rainbow, except that the refraction is different with ice crystals than with raindrops.