The predominant wind is from the east, and the air cools aid forms rainclouds as it tries to rise over the mountains in the center of the island. Then warms again as it descends down the eastern slopes.
So the eastern (Hilo) side is pretty lush jungle, and the west(Kona) is desert.
With snowy mountains in between.
It's interesting to see the transition. Lush green grass and vegetation on your left, and as you turn your head right, it goes more yellow and then completely dry desert on your right.
It's almost like you can see the line across the terrain.
