The prevailing wind direction over the volcanic mountains Mauna Kea and Mauna Loa in Hawaii is generally from the northeast. These winds are known as the trade winds, which blow consistently from the northeast across the Hawaiian Islands.So, the wind typically blows from the northeast toward the southwest over Mauna Kea and Mauna Loa. This is why the northeastern slopes of these mountains tend to be wetter and lush, while the leeward southwestern slopes are drier.