Do you know which is The best place in the world to see rainbows?

 If you're an avid rainbow gazer and want to get your fill of the beautiful phenomenon, look no further than the state of Hawaii. A study published by the American meteorological society in 2021 noted that the area's "mountains produce sharp gradients in clouds and rainfall, which are key to abundant rainbow sightings." Air pollution, pollen, and a large amount of cresting waves also help to put Hawaii at the top of the list when it comes to rainbow quantity and quality.

In the study, The Secrets of the Best Rainbows on Earth, Dr. Steven Businger explains that rainbows found in the US state are so stunning that visitors and locals alike frequently leave their cars by the side of the road in order to photograph the brilliant bands of light. They are commonly seen in the spray blown up by the wind associated with large, fast-moving wave crests that break near the shore. One reason is that Hawaii is located at ∼20°N latitude in a region of the subtropics that is dominated by the Hadley cell, which results in subsidence and generally clear skies over Hawaii and produces prevailing northeast trade winds. 

Hawaii’s trade wind weather is characterized by convective showers with clear skies between the showers, and according to the study, the spacing between the showers is sufficient to allow sunlight to reach the rain beneath the showers, producing optimal conditions for rainbow sightings. At night, a warm sea surface heats convection from below, while radiation cools cloud tops, resulting in deeper rain showers in the morning that produce rainbows in time for breakfast. A critical factor in producing frequent rainbows is the mountainous character of the Hawaiian Islands. Although each Hawaiian island has unique topography and attendant orographic affects, in every case the mountains produce sharp gradients in clouds and rainfall that are key to abundant rainbow sightings.