Rainbow, moonbow, or a combination of both
Rainbows are associated with rainy days, on which the Sun breaks through, but the classic rainbow also has a nocturnal variant. Known as a lunar fogbow, is produced in the same way as a rainbow – only with the Moon as the light source instead of the Sun. You can experience the phenomenon if you look at rain or fog with the full moon behind you. The water drops refract and reflect the light. It's a spectrum, but because human colour perception is poorer at night, the bow looks white. This photograph also includes an aurora (on right).