We see Rainbow in an arc Form but How can we see a circular rainbow?

How can we see a full Rainbow?

A full rainbow is a complete circle, but on the ground, we typically see only an arc because the ground obstructs the lower half. To see a full circular rainbow, specific conditions are required:

1. View from an Elevated Position: You need to be high enough, such as in an airplane, on a tall mountain, or at the edge of a tall building, with no ground to block the view.
2. Light Source Behind You: The Sun (or another light source) must be directly behind you, and the atmosphere ahead must contain water droplets.
3. Rain or Mist Below: There must be rain, mist, or spray in the air below your viewing position to create the necessary refraction and reflection of light.
4. Clear Weather: The sky should be relatively clear behind the rain or mist to allow sunlight to pass through unobstructed.

A perfect spot for observing a full-circle rainbow is during a flight when the Sun is behind the plane, and you’re looking down at rain or mist below. The phenomenon is most striking under these conditions.