A thicker cloud deck can create a much tighter ring around the sun or moon. Too thick of a cloud layer will block the light completely and prevent a halo from forming even if the crystals are all ...

A rainbow is made from rain ... There's a weather saying: "A ring around the sun or moon, means rain or snow coming soon." That proved to be true because it has been a very rainy Monday.

So when the sun is behind you and the rain in front of you, you see a rainbow ... as a circle because there is nothing in the way to stop you seeing light reflected from all around.

Sometimes, you might even see hints of rainbow colors within the halo ... They can be mistaken for sun dogs: While sun halos form a full circle around the sun, a similar phenomenon called a ...