Hawaii Islands Droughts, Winds, Moisture, Precipitation, Rain

Blowing across miles of open ocean, winds arrive in Hawaii laden with moisture. As they rise over the mountains the winds are cooled and drop their moisture, with the northeastern sides of the islands usually receiving the most rain. The wettest belts can receive upwards of 450 inches of rain a year.

Maximum precipitation typically occurs between 2,000 and 6,000 feet above sea level, depending on the form and height of the island. In one year, more than 600 inches of rain was recorded on Kauai at an altitude of 5,170 feet.

Above 6,000 feet, precipitation decreases making the high peaks semi-arid. As the winds descend the leeward slopes, they become warmer and drier, causing arid and semi-arid climates on the leeward sides of the islands. Annual rainfall on the leeward coasts can be 10 inches or less. However, on the island of Hawaii, known as the "Big Island", the mountains are high enough to pierce the trade winds. This creates eddies in prevailing southwest winds on the leeward (Kona) side, so that the climate in the leeward districts is fairly wet.

In contrast, other low-lying Hawaiian islands, such as Kahoolawe and Lanai, are sheltered from the trade winds by other islands and consequently are very dry.

Drought