All the rainbows I have ever seen were about 180 degree arcs (about half a circle). My home is at about latitude 40 degrees north, and I have seldom traveled further north than about 55 degrees, and never further south than about 40 degrees.

Many years ago I speculated about rainbows, which always seem to be cut off at the horizon.

I often wondered if rainbows might form a complete (or nearly complete) circle at more extreme latitudes. Say 80 or more degrees north/south.

Yesterday on a golf course, there was a sprinkler watering the fairway. As I approached it, I saw a rainbow about 10 feet in diameter (say 3 meters) which was about a 270 degree arc (about 3/4 of a circle). This made me think about the rainbow question again.

Does anybody know if a natural rainbow can be a complete circle? Do any of you live at an extreme latitude? If so, have you seen rainbows which are much more than half a circle?