HUNTSVILLE, Ala. – Did you see a halo around the sun Wednesday?
If you did, you spotted an atmospheric optical phenomenon known as a 22-degree halo.
Earthsky.org explains it very simply: “Halos are a sign of high thin cirrus clouds drifting 20,000 feet or more above our heads.
These clouds contain millions of tiny ice crystals. The halos you see are caused by both refraction, or splitting of light, and also by reflection, or glints of light from these ice crystals.”
It is called a 22-degree halo because the ring has a radius of approximately 22 degrees around the sun or moon.
According to the site Atmospheric Optics, the halo remains the same diameter no matter what position the sun is found in the sky.
At times, portions of the circle may be missing, so only a segment can be seen.
Sun halos can be seen when thin, wispy cirrus clouds are present in the sky. These clouds are often present a few days before an on-coming storm system, or even behind a departing storm system.