Answer: Being on the windward side of the island, moisture floats in off from the pacific ocean.
Explanation: In fact, Hilo is the wettest city in the United States. Being on the windward side of the island, moisture floats in off the Pacific Ocean and begins to rise as it meets the slopes of Mauna Loa and Mauna Kea. Hilo is the beneficiary of substantial moisture arriving in the form of rain.