Why is there a blush around the moon?

It is a halo phenomenon caused by the refraction of light.

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. The size of the halo depends on the attitude of the ice crystal. If the light enters from a specific position of the ice crystal, a larger halo will appear. The appearance of solar halo or lunar halo often indicates that the weather will change to a certain extent.

Time of appearance

Solar halos mostly appear in spring and summer. There is a folk proverb that "it rains in the middle of the night when the sun is dizzy, and it is windy at noon when the moon is dizzy", which means that if there is a solar halo, it will rain in the middle of the night, and if there is a lunar halo, it will be windy at noon the next day. To some extent, solar halo can be a precursor of weather change, and it may turn cloudy or rainy, but there is no scientific basis to say that this phenomenon can predict climate drought, floods and earthquakes.