FARMERSBURG, IN (WTWO/WAWV) – A rainbow isn’t really a “thing” and it doesn’t exist in a particular “place.” It is an optical phenomenon that appears when sunlight and atmospheric conditions are just right—and the viewer’s position is just right to see it. (Rainbow at Suuroy, Faroese Islands. Photo by Erik Christensen.)
A full rainbow is actually a complete circle, but from the ground we see only part of it. From an airplane, in the right conditions, one can see an entire circular rainbow. (Credit: NOAA.)
A secondary rainbow appears if the sunlight is reflected twice inside the water droplets. Secondary rainbows are fainter, and the order of the color is reversed, with red on the bottom. (Credit: Leonardo Weiss via Wikimedia Commons.)
And there are a variety of rainbows. Click on the link to see just how many.
So, what are the ingredients to create these popular visuals?
First, you must be between the sun and the rain.
It must be within a few hours of sunrise or sunset.
The rainbow will appear at the point opposite of the sun.
Larger raindrops often create bright bands for the rainbow.
With spring and summer rains coming, enjoy a rainbow now and then.

SciJinks: https://scijinks.gov/rainbow/