Empirical orthogonal function analysis was applied to monthly mean rainfall data at 63 station in Hawaii encompassing a 37-year period. Major rainfall patterns in order of importance (E1-E3) proved to be trade wind, southwest wind and convective rainfall on an annual basis; trade wind, southwest wind and frontal rainfall during winter, spring and fall season; and trade wind, tropical disturbance and convective rainfall during summer. Trade wind rainfall (E1) explains most rainfall variamce in summer and least variance in winter. Composite rainfall maps for wet and dry winter and summer half-years indicate the contributions that specific eigenvector patterns make to these anomalies. Comparisons between Hawaiian rainfall and El Niño reveal that most (not all) El Niño winters in Hawaii are dry. Lack of trade wind rainfall is the primary cause.