Have you ever seen a large ghostly disc around the Moon on a cool, calm, hazy night? If so, you have likely seen what is called an “Ice Halo” or “22° Halo.” Not only can the Moon display these ghostly rings of light, but the Sun does so in the day time too.
22° halos are visible all over the world and throughout the year; look for them whenever the sky is wispy or hazy with thin cirrus clouds – even in the hottest countries.
So what are they and why do they appear? (more…)