Usually I've seen sundogs last maybe 15 minutes to an hour. In Grand Forks, ND today it was sunrise to sunset with sundogs visible. I've never seen them last that long. Plus there was a circumzenithal arc also visible more or less have of the day. Although it was really, cool. It's been freezing outside, the wind chill hasn't been above zero all day. What is a sundog? Well sundogs (parhelia, mock suns) are, with the 22º halo, the most frequent of the halos. Look for them, especially when the sun is low, at each side and about 22° away. This is the same distance or more than the common circular halo. Sundogs reveal that the clouds are hosting horizontal plate crystals. These plates drift slowly downwards like leaves with their large faces almost horizontal.
