It’s Cold Enough In Sioux Falls To See ‘Sundogs’

January 2022 arrived in South Dakota with mild (for a South Dakota winter) temps but things quickly devolved into single-digit highs and crazy wind chill figures.

One interesting side effect of those bitterly cold temps is an atmospheric phenomenon called 'sundogs'. When the sky is mostly clear and the sun is bright, you can see partial rainbows on either side of the sun.

According to the National Weather Service, sundogs 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. The colors usually go from red closest to the sun, out to blue on the outside of the sundog. Sundogs are also known as mock suns or parhelia, which means "with the sun". Sundogs can sometimes be a precursor to snow.

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While sundogs can be fairly common in winter around South Dakota, its elusive cousin the moon dog is rare.  A moon dog features patches of light at 22 degrees to the right and left of the moon, but is typically seen when the moon is a quarter full or more.