Have you ever seen the entire circle of a rainbow?

Not personally.
But it sure looks neat.

Per usual, Wiki has a lot of good reading on the subject.

A rainbow does not actually exist at a particular location in the sky.
Its apparent position depends on the observer’s location and the position of the sun…
The bow is centred…below the horizon…
Exceptions occur when the observer is high above the ground,
for example in an aeroplane, on top of a mountain, or above a waterfall.

I’ve seen it quite a few times where I live. (In Alberta Canada)
Usually in the winter when there are lots of ice crystals in the air before a cold snap you can see a “rainbow” around the sun.

They’re are known as “sun dogs” at least where I’ve heard it and it means cold weather is on the way.

I’ve never seen a full circle rainbow but they are beautiful in the pictures.

Am trying to decide which phrase I like better: cold snap or sun dogs.

My parents told me that they saw a full-circle rainbow from a mountaintop in Hawaii. For some reason, they’re not answering the phone right now, and nothing pops up on my google. Blech. I’ll try back.

I’ve seen it twice, both times in Florida, over a bay. One of them was a double, a full circle within a full circle.

Here’s six rainbows!

http://antwrp.gsfc.nasa.gov/apod/ap070912.html

Never…that would be a sight to behold though!

honestly i didn’t know that was even possible! i’ve seen 2 &1/2 rainbows though. that was interesting.