There is a large variation in climatic conditions here. Snow and ice at the mountain tops, alpine forests farther down, rain forest and desert lower. Temperature, humidity, rain, and wind are all driven by altitude and location with respect to the mountains. The prevailing winds are Trades , winds out of the northeast. When trades are blowing, it is cooler in Paauilo and Waikoloa, probably raining in Waimea.
Winds blow, it becomes warmer and more humid over most of the Island.
As is evidenced by trees permanently warped around the island, Trades do prevail. The east side of the Island gets rained on. Some places on the east side get over 100 inches a year. Not far from where we live, they got 19 inches in 4 days. The west side of the Island is in the rain shadow of Mauna Kea and Mauna Loa.