Looking up at the moon tonight there's a large almost perfect circle in the clouds - what is it?

Question

Here in SW France there is, as described, a strange circular hole in the clouds through which the moon is in the middle. What sort of metreological phenomena is this and what does it signify will happen to the weather?

Answer 1

This is most likely a "corona" or crown. It is due to diffraction of light when a thin veil of cirrus clouds composed of tiny spherical water droplets bend the light as it passes close to the moon. Infrequently there is a circular rainbow outside the corona called "Bishop's Ring"

Answer 2

Its only an apparent "hole", the cloud actually goes right across, but because of the way the light is refracted through the ice crystals of the cloud, there is a darker area close to the moon and a circle and lighter area outside it.

Its the same phenomena that refracts sunlight through rain to make a rainbow.

Answer 3

It sounds to me like the 22° halo which forms when a veil of cirrostratus cloud is over the sun or the moon. The light is refracted and reflected through ice crystals with faces at 60° to each other (the commonest ice crystal) and produces the halo. There are images of lunar and solar 22° haloes here:
http://www.meteoros.de/arten/ee01e.htm
You will find explanations and images of many other atmospheric phenomena on that site.

Answer 4

When thin clouds scud across a bright moon it is often surrounded by a bright disk and faint colored rings, a "lunar corona".

Lunar coronae (plural) usually are visible when ice crystals high in the atmosphere are illuminated buy the sun's reflection off the moon. They can sometimes be created by clouds of pollen and other pollutants, as well.

The weather is usually quite cold and clam when these are visible. They may not necessarily forecast any particular impending weather event, but snow could be likely.

Answer 5

Locally, we call this a "moon dog". Sometimes in the winter you will also see a similar circle around the sun called a "sun dog". As others have said, it's caused by ice crystals high in the atmosphere refracting the light of the sun or moon.

Answer 6

It may be a halo or carona.
A halo is produced by refraction of light by ice crystals that are present in cirrostratus cloud.
A carona is produced by diffraction of light by water drops present in altostratus cloud.

Answer 7

a full moon that is encircled with a beautiful ray of light

Answer 8

Johnnie Frostie is coming your way !!! wrap up warm lol Xxx

Answer 9

its the hole santa will apear from merry christmas from england my friend

Answer 10

halo