A solar halo is an optical phenomenon caused by sunlight passing through ice crystals in high-altitude cirrus clouds. The ice crystals bend the light at a 22° angle, creating a glowing ring around the Sun. • This ring is usually white or faintly colored, like a washed-out rainbow. • Halos are most common when the sky has thin, wispy clouds at about 5–10 km altitude. • They often signal that a weather change (like rain or snow) is coming, because cirrus clouds usually appear before a storm. The s