Here's why Hawaii is the rainbow capital of the world

Hawaii is home to some of the brightest rainbows on Earth, thanks to a unique set of circumstances.

Cultural significance and a unique combination of region-specific circumstances make Hawaii the best place on the planet to enjoy rainbows, according to a new publication piece in the Bulletin of the American Meteorological Society.

The article, penned by atmospheric scientist Steven Businger, argues Hawaii's location in the subtropical Pacific means the weather is dominated by wind and frequent rain with clear skies in between.

And that's just one of the factors make Hawaii a rainbow haven.

"At night a warm sea surface heats the atmosphere from below, while radiation to space cools cloud tops, resulting in deeper rain showers in the morning that produce rainbows in time for breakfast," Businger, professor in the UH Mānoa School of Ocean and Earth Science and Technology, says in a statement.

Hawaii's mountains also play a role. They push trade winds upwards, leading to cloud formation and rainfall. Without them, Hawaii would be a "desert," receiving only about 431 mm of rain annually, Businger says.

Daytime heating drive island-scale circulation, and when the wind is lighter, showers that form over ridge crests overlooking Oahu and Kauai, setting the scene for spectacular rainbows.

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Lastly, Hawaii's remote location helps keep the air clean and free of pollution and pollen, leading to bright rainbows featuring the full colour spectrum.

CULTURAL SIGNIFICANCE

Rainbows are deeply embedded in Hawaiian culture.

"In Hawaiian mythology the rainbow is a symbol of transformation and a pathway between Earth and Heaven, as it is in many cultures around the world," Businger says.

"The cultural importance of rainbows is reflected in the Hawaiian language, which has many words and phrases to describe the variety of manifestations in Hawai'i. There are words for Earth-clinging rainbows (uakoko), standing rainbow shafts (kāhili), barely visible rainbows (punakea), and moonbows (ānuenue kau pō), among others."

You can catch rainbows year-round in Hawaii, but the best time to see them is during the rainy season, which runs from November to March.

Thumbnail image courtesy: Pexels/Jess Vide.