why is there a halo around the moon

That glowing ring is called a lunar halo , and it’s mostly a neat bit of atmospheric optics, not anything mystical.

Quick Scoop

• A halo appears when moonlight passes through tiny ice crystals in high, thin clouds (cirrus or cirrostratus) about 20,000 feet up.

• Those ice crystals are usually hexagon-shaped , so they bend (refract) the light by about 22 degrees, creating a ring the same apparent size every time (a “22-degree halo”).

• The ring often looks white, but the light is actually split into colors like a faint rainbow, with red on the inside and blue on the outside—our eyes usually aren’t sensitive enough at night to see the full spectrum clearly.

• These ice-crystal clouds often show up a day or two before a warm front or storm , which is why old weather lore says a ring around the Moon can mean rain or snow is on the way.

Tiny story version

Imagine the upper atmosphere quietly turning into a giant glass lens made of countless floating ice prisms. The Moon shines through them, its light gets bent at just the right angle, and your eyes see a perfect ghostly circle, like the sky briefly decided to give the Moon its own glowing crown.

TL;DR: There’s a halo around the Moon because its light is being bent by hexagonal ice crystals high in the atmosphere, forming a 22-degree ring that sometimes hints at incoming bad weather.

Information gathered from public forums or data available on the internet and portrayed here.