On the Kona Coast, a unique summer maximum rainfall pattern occurs. Two large mountains, Mauna Loa and Hualelai, effectively block prevailing winds. Ocean-land temperature differences generate local diurnal variations in wind. Surface heating causes upslope winds during the day that create convectional rainfall at middle elevations (the "coffee belt") in the afternoon. Wind direction reverses at night as cooled mountain air moves downslope. Increased surface heating in summer intensifies this process resulting in the only sum mer rainfall maximum in the state.

Highest solar radiation occurs along leeward coasts and atop the highest mountains. The pat terns on the map result from spatial differences in the amount of solar radiation absorbed and reflected before reaching the ground. Factors effecting solar radiation absorption include air pollutants, distance above sea level and, most significantly. clouds. The process that produces clouds and the extreme spatial variations in rainfall are also responsible for the radiation pattern.