The Scientific Reason Why Hawaiian Sunsets Are So Beautiful

The colors of the Hawaiian sunset intensify just after the sun sets.
These are all photos of the same sunset. The colors of the Hawaiian sunset intensify just after the sun sets.

Hawaiian sunsets are spectacular. They draw visitors to the islands from all over the world not just because of their stunning vibrant colors, but also because Hawaii is one of the best places to view the green flash. The vivid colors result from a perfect cocktail of conditions, regularly found in Hawaii, but less common in most other places.

Why the Sunset Changes Colors

During the day, the sky appears blue because dust, water vapor, and other gases in the atmosphere scatter blue and some violet light. Of course, other wavelengths of light bounce off the tiny particles, too, but the scattering of blue light is nearly ten times more intense than red scattering. The effect is called Rayleigh scattering and is named for John William Strutt, 3rd Baron Rayleigh, who described it. When the sun rises or sets, the light passes through a much larger column of atmosphere to reach your eyes, so more scattering occurs. The lower the sun is on the horizon, the steeper the angle, and the more orange, pink, and red you see.

Why Hawaiian Sunsets Are Special

All sunrises and sunsets have the potential to be colorful, but Hawaii gets an added boost:

  • Volcanic dust high in the atmosphere aids scattering. On the Big Island of Hawaii (Kona), Kilauea has been erupting continuously since 1983. That’s a lot of volcanic dust and vog (volcanic smog or haze)! The trade winds push the dust across the island from East to West, so sunset is even more likely to be colorful than sunrise.
  • Hawaii gets help from geography. The islands are located 20° north of the equator and 155° west of the Prime Meridian in the Northern Hemisphere. The position gives the islands balmy temperatures year-round, which means there’s enough heat to put a lot of water vapor into the air. The humidity aids scattering, intensifying colors.
  • The sun sinks into the Pacific Ocean, far from any land mass that could disturb the atmosphere or break the horizon line. The angle of a sunset over water is as good as it can get.

Sunset Is Best After the Sun Actually Sets

The angle of the sunset also explains why the colors intensify after the sun dips below the horizon. Light from the sun still strikes the air, including the humid layer right above the water, and the clouds higher in the sky. The steep angle produces the gorgeous deep reds, pinks, and oranges, while the rest of the sky develops shades of purple, blue, and sometimes green, and gold. If you watch a Hawaiian sunset, linger a few minutes after the sun has set and watch the colors develop.

Fun Hawaiian Sunset Facts

If you watch the sunset with a group of people, particularly near a resort, there’s an excellent chance you’ll witness the Hawaiian Pū ceremony. At sunset, it’s traditional to blow a shell horn. The first note of the horn is blown when the bottom of the sun touches the water. Three more notes are blown, with the last sounded when the sun disappears. The notes call four Hawaiian gods. A final note of goodbye and Mahalo (thanks) ends the ceremony. The Pū is not blown at night, because then it might summon darker spirits.

It gets dark quickly after sunset. Expect the last light to fade from the sky within about 15 minutes.