Rainfall in Hawaii

It's surrounded by moist air from the Pacific Ocean. The mountain's size and shape make it perfect for catching trade winds from the east. These winds, which blow 250 days of the year, are funneled into the mountain's steep crater.
The breezes rise to 5,000 feet, the ideal elevation for moisture to condense into rain clouds. Most of the water descends on the island's eastern, or windward, side. The western, or leeward, side stays considerably drier.
The secret to being happy here, Spencer says, is "to figure out how to live with nature and not work against it, because you're never going to win. You work with the water. You let it go where it wants to go. You do what you can to direct it."
At the end of April, the rainy season will have passed, and the island will bask in the steady Pacific sunshine that draws so many mainlanders. Spencer will plant vegetables. The dry weather will last for about a month.