What is the phenomenon that there is an aperture around the moon?

Lunar halo is an optical phenomenon in nature. It is a color aperture formed by the refraction of ice crystals when the light of the sun or the moon passes through high and thin white clouds (cirrus, cirrostratus or cirrocumulus), and the color arrangement order is in infrared violet. The aperture around the sun is called solar halo, and the aperture around the moon is called lunar halo.

Usually, we have more chances to see a lunar halo than a solar halo. Lunar halo is also called "wind circle". Moonlight is refracted by clouds, forming an aperture around the moon, which can be used as a sign of weather changes.

Possible consequences of certain symptoms.

The appearance of solar halo or lunar halo often indicates that the weather will change to a certain extent. Generally speaking, a solar halo means it may rain, while more lunar halos mean it will be windy. So there is a folk proverb: "The sun is dizzy in the middle of the night and the moon is dizzy at noon."