Full circle rainbow
© Brad Hudson
Yes it's possible to see them... when you are just up high!

This was the case of Brad Hudson, owner of The City Arborist in Greenville, SC.

When sunlight and raindrops combine to make a rainbow, they can make a whole circle of light in the sky. But it's a very rare sight. This rare sky phenomenon was captured on January 16, 2016.

Sky conditions have to be just right for this, and even if they are, the bottom part of a full-circle rainbow is usually blocked by the horizon. That's why we see rainbows not as circles, but as arcs across our sky. If you could get up high enough, you'd see that some rainbows continue below the horizon seen from closer to sea-level.

Brad Hudson with The City Arborist, LLC, a Greenville tree care company was at a 400-foot elevation when he snapped the full circle rainbow.

In 2014, a perfect rainbow circle was filmed from the Skylon Tower Revolving restaurant at Niagara Falls, Ontario: