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Green Sunsets Are 100% Real

Looking west from Kauai. Moments later, the sun turned green. And my camera pooped out.
Looking west from Kauai. Moments later, the sun turned green. And my camera pooped out.

POIPU, Kauai – I never thought I’d see the fabled “green flash.” After decades of squinting toward the evening horizon, hoping to see what my 8-year-old brain had envisioned as a fountain of green light erupting from the sun, I’d conceded defeat. In fact, one could say I was a member of team Tanqueray Flash—a term I’d serendipitously encountered in a book describing Kauai’s hiking trails.

“The only green flash anyone’s ever seen is through the bottom of a Tanqueray bottle,” the author’s father supposedly grumbled at a columnist who’d described the phenomenon in the LA Times. Gin bottles? Those I knew something about. Green sunsets, not so much.

But two Sundays ago, as I stood on Kauai’s south shore, the sun defied my expectations and turned green as it dove into an ocean spotted with sea turtles and humpback whales. It wasn’t just any green, either: For a few moments, the setting sun was a vivid, otherworldly hue that matched my conception of alien slime.

Somewhat unbelievably, the sun pulled the same trick the next evening, when it again transformed itself into a glimmering green—and it did the same thing again two nights later as it waved goodbye to 2015. Each time, the peculiar color appeared at the fringe of the descending disk, then bled through the rest of the sun as it slid into the sea, leaving the ocean temporarily wearing a ridiculous green cap.

It was nothing like the image my 8-year-old brain had conjured, and spectacularly better than staring through an empty bottle of Tanqueray.

Yet based on my three observations (small sample, I know), “flash” isn’t quite the word I’d use to describe the phenomenon. To me, “flash” implies something quick and bright, like lightning or a camera flash, neither of which is similar to what I saw. The green color was fleeting, to be sure, but it simmered rather than burst, and oozed instead of erupted. It was more of a “green glow” or a “green smear.”

Stages of a green flash seen near Santa Cruz, CA. A bit of blue is creeping in here, which can happen when the air is incredibly clear. (Brocken Inaglory/Wikipedia)
Stages of a green flash seen near Santa Cruz, CA. A bit of blue is creeping in here, which can happen when the air is incredibly clear. (Brocken Inaglory/Wikipedia)

Regardless of what you call it, the green flash occurs because Earth’s atmosphere bends and scatters light from the departing sun. When viewing conditions are just right, green wavelengths reach our eyeballs and the rest are filtered out. Normally, “just right” conditions include a clear, unpolluted horizon that’s free of clouds and haze, which more or less describes a lot of places that aren’t Los Angeles or Beijing; people most commonly report seeing green flashes over the ocean, though a watery horizon is not a requirement.

Green colors can also appear at sunrise, though they’re tougher to see than at sunset, and can sometimes appear just above the sun, rather than being smeared over its disk. And, it turns out, 8-year-old me wasn’t totally wrong after all: A rare class of “flash” actually appears as a ray extending upward from the sun.

In 1882, Jules Verne published Le Rayon Verte – the Green Ray – in which he dreamed up an old Scottish legend that suggests anyone who sees a green flash will never again make a misstep in matters of the heart. I doubt that’s true.
In 1882, Jules Verne published Le Rayon Verte – the Green Ray – in which he dreamed up an old Scottish legend that says anyone who sees a green flash will never again make a misstep in matters of the heart. I doubt that’s true.

So why it is so unusual to see? One explanation is that under normal circumstances, the green flash is so quick that it’s imperceptible unless an inversion layer in the atmosphere helps the color stick around for longer. But I’m not really sure. I suspect it’s something like the recipe I got from one of my favorite bakeries for the most delicious (vegan) cupcakes I’d ever met—even after following the recipe to the letter, my cupcakes didn’t turn out as well. As with those mysteriously good cupcakes, the recipe for green flashes probably involves a bit of secret sauce, because even under the best circumstances, it’s tough to predict when it will appear.

I’m told that seeing the phenomenon from Kauai is nothing special, though it is sometimes extreme enough to temporarily stop table service at restaurants in town. What this suggests to me is that visiting Kauai in winter is pretty much a must-do, for reasons that have nothing to do with mai tais that come in pints, swimming with sea turtles, and braving extremely muddy trails that take you through some of the rainiest places on Earth. We’re used to seeing a lot of colors at sunset, but green isn’t one of them—and when it does appear, the green flash is exquisite.

15 thoughts on “Green Sunsets Are 100% Real

  1. I observed the Green Flash many years ago when on a boat in the Caribbean. In my case the color was bright and pure (seemed to be a single wavelength) and lasted about half a second.

    The most curious thing to me about the phenomenon was that almost everyone I told about the experience, from my companions on the boat on, denied that I had seen it. Eventually I came across photographs (which many people assured me were fakes, on no factual basis). This strikes me as odder than that an atmospheric phenomenon might be rare.

    1. Dear Gordon, I don’t think the mass denial has anything to do with the event being rare. It’s just that people who aren’t looking for it don’t see it when it happens. It seems to be very fleeting, & this article does a good job explaining what to look for. On vacations in Mexico, I tried to look for it at sunset, but didn’t really see it. I was so excited to see these pictures; it has cleared up a lot for me. Because I know of such optical phenomena sun dogs & “glory”, I know what to look for. I am also an avid birder. When I tell people what I’ve spotted in my backyard, they think I’m crazy, but I always tell them, “It’s all there, just for the looking.”

      1. Tenicatita — You are so right about the fact that people who aren’t looking for it are extremely unlikely to see it. This ties right into what you said about things being there for the looking. It does help, though, to be trained [or to train yourself] to observe; most people seem to gloss over and ignore the majority of what they see.

        Best —

  2. One evening on Clearwater Beach, Florida’s shoreline I set my video camera on a tripod to capture the sunset. I wasn’t expecting it, but as the sun dipped below the horizon, there for a second was the green flash. When I viewed the video, I was horrified to find that a tourist had stepped in front of my camera lens at the very moment the green flash occurred. Perhaps four frames captured the first hint of green, the rest was obscured by the person’s head. Murphy’s law.

  3. I imagine that the reason it occurs mostly over oceans is that, on land, the horizon is usually elevated to some degree. Even someplace flat (like, let’s say, Central Illinois) there may be trees in the distance raising the horizon. With an elevated horizon the light will not be going through as much atmosphere and you won’t get enough bending and scattering.

  4. I found myself nodding along to the article – I saw my first green flash in 2014 in Camps Bay, Cape Town, South Africa. As an astrophysicist, I had been hoping and wishing to see it all my life. People in the bar I was in audibly gasped at the green hue that was briefly cast over the surroundings. I’ve been reliably informed it’s possible to see a green flash at sunrise. In fact, it’s apparently easier to see at sunrise as your eyes aren’t ‘burnt out’ from staring at the sun.

  5. I have seen a green flash, a blue flash and a violet flash, but frustratingly habe never been able to get a photo. Well done for the shots above.

  6. My mother’s favorite author, John D. MacDonald wrote about the green flash in his series of books set in Florida. She’s been gone for 40 years but whenever I read them she is with me. I’m so happy to know that it is real and the next time I am in Florida I’ll be looking for it. Thank you, thank you!

  7. In 1986 Eric Rohmer’s film “The Green Ray” was released. I don’t remember if it actually showed the green flash, but it was a wonderful film.

  8. I started watching for the Green Flash decades ago, and saw one once over water. I have heard it called “a Glimpse of Paradise “

  9. I live in San Diego, Southern California and every chance I get I watch a sunset hoping to see a green flash. I have been fortunate to see several green flashes in the Point Loma Sunset Cliffs area. It’s truly amazing and when you see it there’s no mistaking it. People stand in silence waiting for the last beam of sun light to sink below the horizon. If you are lucky you will see a tiny glowing green bubble replace the sun and dissolve in the horizon in a flash of a second. The standing crowd roars in applause in celebration of seeing the green flash. Truly wonderful.

  10. Fifty years ago as a seaman I first saw the green flash off the West Africa coast. I saw it on several trips in this are in the 60’s. One of my fellow seamen used to call it ‘Paddy’s Pennant’.

  11. My wife and I were fortunate to see the green flash from Maui in 2013. And, because a friendly tour bus driver had given us the following tip, we saw it twice in the same sunset: Watch the sun set while sitting down. Then, when you see the green flash, stand up and see it again. It worked!

  12. A few years ago I witnessed a green flash that would be better described as a green ray. It wasn’t brief, there was time to pull over the car to get a better look, and it was very pronounced, a beam of green sunlight was cast up vertically from a generally green sunset. I was on the west coast of Ireland at the time, a couple of miles back from the coast so I imagine an even more spectacular view would have been possible on the shore.

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