Steven Businger professor at UH School of Marine and Earth Science and Technology explains that there are four factors that contribute to the beauty of the colorful Hawaiian sky.
First, the position of the islands in the atmospheric circulation known as the Hadley Cell ensures that Hawaii is visited by the northwest trade winds on an almost daily basis. This produces patches of convective rain, interspersed with areas of clear sky, allowing sunlight to mix with rainfall and produce rainbows.
The warmth of the night provided by the sea causes the air to rise in the morning and allows rainbows to form. In contrast, a night rainbow is produced when temperatures rise throughout the day, creating air currents.
“Under these conditions, heavy rain forms on the tops of the ridges above Oahu and Kauai in the afternoon, producing lush rainbows as the sun goes down,” Businger said as quoted by Sindonews of IFL Science.
The topology of these mountains is another key factor in the formation of the Hawaiian rainbow, as the peaks force the winds to rise and cool, resulting in rainfall. Without these mountains, Hawaii would be a rainless desert.
Finally, Hawaii’s remote location ensures that the air is largely pollution-free which means there are very few aerosol particles that can scatter sunlight and detract from the beauty of a rainbow.
All of these factors combine to allow Hawaiian rainbows to last for hours. Even Businger claims that rainbows in Hawaii can last up to 6.5 hours during summer and 8.5 hours in winter.
“It is not surprising that rainbows are very prominent in Hawaiian mythology and culture. In the Hawaiian language, for example, there are words for a rainbow stuck to Earth (uakoko), standing rainbow (kāhili), barely visible rainbow (punakea), and rainbow. (ānuenue you pō), “explained Businger.
– .
