“When you watch the sunset, look out for the green flash”.
You’ve probably heard those words uttered by a friend or acquaintance. The web is awash with images showing the green flash and people asking how they can see it. But what is it, why does it appear, and how can you see the elusive green flash at sunset?
What Is the Green Flash at Sunset?
The existence of the green flash has long been debated, but it’s a real phenomenon.
As the sun dips over the horizon, its light is bent by the atmosphere and this separates the colors based on their wavelengths.
Colors with long wavelengths (including red, orange, and yellow) don’t refract as strongly as those with shorter wavelengths (including green and blue).
The result is that blue and green light is scattered while red and orange light is absorbed. A green ray of light appears most prominently during this time and it is enhanced by the atmosphere, which acts as a lens and magnifies the hue.
It’s not always a green flash, either. On a very clear day, you may even see a blue flash.
Green flashes can also appear in several forms, including a mock-mirage green flash and an inferior-mirage green flash. To the uninitiated, it’s still a green flash and it still makes for a mesmerizing sight.
How To See Green Flash Sunset
To see a green flash, you need a little luck and a lot of patience.
You’ll need a clear day when there are no clouds on the horizon to block the light. You will also need a distant horizon, so settle down on a mountaintop or look out the window of a tall building.
Boats and beaches are also good places to see green flashes.
When looking for green flashes, it’s important not to stare at the sun as you will damage your eyes. It seems like an obvious statement to make, but you’d be surprised at how many people fail to follow this advice.
Wait for the sun to dip over the horizon before you cast a glance.
Sunset is the best time to see a green flash. They may also appear at sunrise, but they are less frequent.
The Best Places to See Green Flashes at Sunset
Green flashes are not as common in big cities, where pollution may prevent them from appearing.
San Diego, California is a great place to see a green flash and they are also commonly seen in Hawaii and Key West. Technically, they can appear anywhere, but you’re more likely to see a green flash on a beach in San Diego than you are on a high building in the Midwest.