Thus, the east sides of the islands experience rainy periods much of the time. As the rising air ascends, two things happen. Second, the process of condensation is so violent and so thorough that by the time the air reaches this level there is generally very little water available anymore. The result is moderate rain at the coastline, much heavier rain on the slopes above, and rather dry conditions on the tallest mountain peaks. In the Hawaiian Islands, the rainiest places are generally about 3,000 feet above sea level.
Nights are usually wetter than days, because the air is cooler to begin with.
As air reaches the crest, it begins to flow downward along the leeward side of the peaks. As air descends, it gets warmer, and its capacity to hold water vapor increases. Also, the higher mountains, above 6,000-8,000 feet, are arid and parched. Click below for a Big Island climate discussion, or continue to read detail about the Island of Kauai. At its highest point, the island rises to about 5,000 feet, very near the typical trade wind inversion height.