The green flash is a real atmospheric effect that can appear for a second or two at the top edge of the Sun as it sets over a clear, distant horizon. It is not a camera trick, an afterimage or a myth. Along the open Pacific horizon off Malibu, Santa Monica, Newport Beach and Laguna Beach, a clean sunset with no haze or clouds on the water gives Southern California a real, brief chance to see it.
What Is the Green Flash at Sunset?
The green flash is a brief green rim, spot or flare at the top edge of the Sun as its last sliver disappears below a distant horizon. It is small. The real effect is a thin, bright green edge or small green dot that lasts about a second or two after the rest of the Sun has set, not a burst that lights up the sky. It happens at the exact moment of sunset, and it can also happen at sunrise, the instant the Sun's top edge clears the horizon.
The green flash is easier to catch at sunset, because you can watch the Sun approach the horizon and know when to be ready. A sunrise sighting requires watching a spot on the horizon before the Sun appears.
The green flash is not lightning, a glow from the ocean or a lens artifact from a phone or camera. It is a real optical event in the sky, caused by how the atmosphere bends and separates sunlight at the horizon. Online posts often mix it up with unrelated green lights, from ship running lights to glowing algae.
Is the Green Flash Real?
The green flash is real and documented, described in atmospheric optics references and in NOAA's overview of optical phenomena. Photos and telephoto video often make it look larger and greener than the naked eye sees. A long-lens shot processed for color can turn a faint green sliver into a vivid green ball, setting expectations the real sky rarely meets. That gap is probably the main reason people doubt the green flash after missing the dramatic version.
The green flash is also different from an afterimage. After you stare at a bright light, including the Sun, your eye can produce a lingering colored ghost image, often reddish or greenish, when you look away. That afterimage comes from the eye, not the sky, and it is one more reason not to stare at the setting Sun while waiting. The real green flash is a brief event at the horizon.
What Causes the Green Flash?
The green flash happens because Earth's atmosphere bends the setting Sun's light and separates its colors slightly, so green light stays visible for a moment after red, orange and yellow have set. This bending is called refraction, and it happens because light passes through air that gets denser toward the ground. Sunlight skimming the horizon passes through the thickest slice of atmosphere of the day, so it bends the most.
The atmosphere bends each color by a different amount, an effect called dispersion. Like a glass prism, it bends blue and violet light the most and red light the least. In theory, that should put a blue or violet rim on top of the setting Sun. In practice, the long, hazy path near the horizon scatters and absorbs blue and violet light far more than green, the same scattering that makes the sky blue.
By the time sunlight reaches an observer at the horizon, most of the blue and violet is gone. Green is the last color strong enough at the Sun's top edge to show as a flash after red and yellow disappear.
Temperature layers just above the ocean add a second factor. When air temperature changes sharply with height over the water, often because the ocean is cooler than the air above it, the Sun's top edge can appear stretched, squeezed or doubled, an effect related to mirages. That stretching can hold the green rim in view slightly longer or distort the Sun so the flash is harder to see. The same beach can show a clear flash one evening and nothing the next under a similar clear sky.
| Condition | Effect on viewing | Southern California example |
|---|---|---|
| Clear, distant horizon | Lets the final solar rim remain visible | Open Pacific view from a west-facing beach or bluff at Laguna Beach |
| Low haze and few horizon clouds | Reduces obscuration of the last solar limb | A clean, post-front coastal evening |
| Strong near-horizon refraction | Can stretch and separate the solar image | Temperature layering over the ocean surface |
| Elevated viewpoint | Can extend the visible horizon slightly | A safe coastal bluff or overlook, not a crowded roadway |
| Marine haze or a low cloud bank | Usually blocks the final limb entirely | Sunset disappearing into a cloud deck before reaching the water |
Good conditions improve the odds, but nothing in the table above guarantees a sighting. The air over a real ocean horizon is rarely uniform, and a thin layer of haze or a wisp of low cloud can block the view after a day that looked clear from the beach.
How Rare Is the Green Flash?
The green flash is uncommon for casual viewers but not rare in the atmosphere when observers watch a clear ocean horizon repeatedly. The effect is tiny, brief and easily blocked. Someone glancing at the sunset once from an inland patio, with hills, buildings or haze on the horizon, is unlikely to see it. Someone who watches a clean Pacific horizon on clear evenings, focusing on the last second of sunset, succeeds far more often.
Two different claims get mixed together. The green flash is rare for casual observers: most people who have watched hundreds of sunsets have never looked for it at the right moment with an open horizon. It is not rare in the atmosphere, because a clear, low view of the setting Sun happens on many evenings along the Southern California coast. The difference comes down to the horizon, night-to-night haze and whether anyone is watching at the right second.
Where Can You See the Green Flash in Southern California?
The best places to see the green flash in Southern California are safe, west-facing beaches and raised coastal viewpoints with an open Pacific horizon. Malibu's coast and bluffs, Santa Monica's beach and pier, Newport Beach and Laguna Beach's coves and overlooks are common choices, not a ranking. At any of them, what matters most is whether the line of sight to the setting Sun is open ocean, not land. Where the Sun sets relative to the coastline changes through the year.
Offshore islands can block the horizon. Santa Catalina Island can cover part of the horizon from some Southern California beaches, depending on where you stand and the time of year. The Sun's setting point moves along the horizon through the seasons, so a spot with open ocean in one season can have the island right where the Sun sets a few months later.
The sheltered, harbor-facing parts of Long Beach often have more blocked views than open beaches farther up the coast, so check the sunset direction and horizon before setting up. Check sunset time, coastal clouds, haze and visibility for that evening and that beach; yesterday's clear sky may not repeat.
How Do You Watch or Photograph the Green Flash Safely?
To watch the green flash safely, wait until the Sun is nearly at the horizon, do not stare at it beforehand and never look at the setting Sun through binoculars, a telescope or a camera's optical viewfinder without certified solar filters. Glance toward the Sun only briefly as it nears the horizon and look away between glances. Watch steadily only in the last few seconds, when most of the disc is below the water and it is dim enough to view comfortably. The NASA solar-viewing safety guidance for eclipses applies too: magnified viewing of the Sun, even partly set, can damage your eyes, and sunglasses do not protect against magnified optics.
To photograph the green flash, frame the shot in advance on the camera's screen, not through a magnified optical viewfinder. Use a long lens or crop so the Sun's top edge is clear without looking through an eyepiece. Use a tripod, because the flash lasts only a second or two and a shaky handheld shot can miss it. For longer direct viewing, use equipment rated for solar observation, as NASA's guidance above explains.
Before heading out, check the sunset time and coastal visibility for your destination. A hazy afternoon can hold enough moisture or particles at the horizon to block the flash even with clear sky overhead, so check conditions close to sunset. WeatherLA's destination pages show cloud cover and visibility for coastal spots like Malibu and Newport Beach, which helps decide whether tonight is worth the trip.
Seeing the green flash takes patience more than luck: an open horizon, a clear last few minutes of daylight and someone watching the exact moment the Sun's last sliver sets. Southern California's west-facing coast offers that combination on many evenings each year. Check coastal clouds and sunset time for your beach, get in position early and watch the horizon closely in the last safe second. Check the Los Angeles marine layer before choosing a night, and see the Southern California red-tide guide for a coastal glow with a very different cause.