"What conditions need to be present for a sundog? I have seen them and would like to be able to look specifically, if the conditions are right." — Michael C.

First, let's explain what these rare, colorful phenomena are. Sundogs are brightly colored spots of light that cause refraction through airborne ice crystals.

Sunlight and ice crystals are needed for sundogs.

These ice crystals are tiny — roughly half the width of a human hair. Since they’re so small, they fall very slowly in the atmosphere.

You also need these crystals to be in the shape of flat hexagons. Think of these as like fancy six-sided dishes you might pick out for your wedding registry, but with a little more thickness.

When the sun is shining through those ice crystals near the horizon, sunlight is bent and dispersed within each ice crystal, splitting it into all its colors like a prism. (If you’re a classic rock fan, think of Pink Floyd’s Dark Side of the Moon album cover.)

What you’ll see then are two bright spots on either side of the sun. Those are the sundogs, also known as “mock suns” or the technical term, "parhelia."

When they appear, they do so in pairs, with two of them roughly the same distance on either side from the sun in the sky, following it like obedient, well-trained dogs.

The red colors of each sundog appear closest to the sun, since that’s bent the least within all the ice crystals.

You can look for these any time of year, particularly when there are milky sheets of cirrus clouds high in the atmosphere. They're more likely to appear within a few hours after sunrise or before sunset.

They’re usually brightest in colder places during a bitter cold outbreak when there are more ice crystals in the atmosphere, sometimes in ice fog near the ground.

How likely are you to see them? It's hard to say; they depend on so many different conditions aligning. Let's put it this way: In my home state of Wisconsin, I would guess one could see these at least two or three times a year, particularly during a bitterly cold air mass in winter.