Rainbows are visible light that we can see broken down into red, orange, yellow, green, blue, indigo, and violet. To see all the colors of rainbow three things must occur. The sun must be high in the sky and must be behind you. Lastly there must be water drops in the air, whether it be from a sprinkler or a small sun show. Sunlight shines off of the water droplets. the rays of light given off the water bends twice. As they enter the drops, the rays bend, then reflect off the back of the drops. The rays then bend a second time when reflecting off the drops into what we see as color. Each drop gives off only one color, so many drops must be present to see a full color rainbow.
Halos can usually be seen as a single ring of color around the sun or moon. Halos are known to occur more frequently than rainbows. To witness a halo you must put first block the sun or moon from your view using your hand or perhaps even a visor. The object is to be able to see only the clouds around it. The halo can be either white, red or orange in the middle, then yellow or blue in the outer edges.