Fascinating!

The following article says many people saw a lunar halo the night before Hurricane Sandy made landfall. Then, the night of the landfall, many in the U.S. Midwest and West witnessed the same.

What causes a lunar halo?

There’s an old weather saying: ring around the moon means rain soon. There’s truth to this saying, because high cirrus clouds often come before a storm.

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. 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.

Read more here:

[link to earthsky.org]