What causes this halo in the sky?
As we approach summer and the sun is coming out you may notice a ring, or halo, around the sun. This unusual sight is caused by cirrus clouds.
Those thin cirrus clouds are around 20,000 feet or higher above us. They are made of tiny, ice crystals. Sunlight through the ice crystals causes the light to split, or be refracted. When at just the right angle, it causes us to see the halo.
The same thin clouds can cause a ring, or halo, around the moon at night.~ spectrumlocalnews
A Sun halo is caused by the refraction, reflection, and dispersion of light through ice particles suspended within thin, wispy, high altitude cirrus or cirrostratus clouds.
The right angle – is 22° – As light passes through these hexagon-shaped ice crystals, it is bent at a 22° angle, creating a circular halo around the Sun.
Scientists call them 22-degree halos – because the radius of the circle around the sun or moon is approximately 22 degrees.
The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear.
That’s why, like rainbows, halos around the sun – or moon – are personal. Everyone sees their own particular halo, made by their own particular ice crystals, which are different from the ice crystals making the halo of the person standing next to you.