Weather Explainers

St. Patrick's Day Myth Busted: The Truth About Rainbows And Nature's Illusions

This St. Patrick’s Day, discover the science behind rainbow formation, how sunlight, refraction and water droplets create an optical illusion, and why you won’t find a pot of gold at the end.

If Not Gold, What's At The End Of A Rainbow?

As St. Patrick’s Day approaches, images of leprechauns, shamrocks, and, of course, rainbows leading to pots of gold flood our imaginations. But while the legend of treasure waiting at the end of a rainbow has been passed down for generations, science tells a different story—one just as fascinating, even if it doesn’t involve hidden riches.

One of the most admired meteorological phenomena, rainbows are formed through a process called refraction. When sunlight passes through water droplets in the air – whether from rain, mist or even fog – it bends and reflects, splitting into the vibrant spectrum of colors we see. This dazzling display occurs because different wavelengths of light travel at varying speeds when passing through water. Longer wavelengths appear red, while shorter ones show as blue or violet, creating the iconic arc of colors.

For a rainbow to appear, three conditions must align: the sun must be behind the observer, the water droplets must be in front, and the sun’s angle must be lower than 42 degrees above the horizon. This perfect mix of sunlight and moisture explains why rainbows often appear after a passing storm.

(MORE: This State Is The Rainbow Capital Of The World)

But what about the “end” of the rainbow? The truth is, there isn’t one. A rainbow is a full circle, but from the ground, we only see part of the arc. The “end” that seems to touch the earth is an optical illusion that changes based on the observer’s position. If you were in an airplane, you might even see a complete circular rainbow.

While science may have debunked the myth of a pot of gold, that doesn’t make rainbows any less magical. Whether seen as a lucky omen or just a beautiful natural phenomenon, they remain a breathtaking reminder of the wonders of light, water, and the atmosphere.

So, this St. Patrick’s Day, if you spot a rainbow, enjoy the view—but don’t waste time chasing it. The real treasure might just be the moment itself.