Resumen
. Rainfall fluctuations in the River Itajaí valley were studied on the annual and interannual plane. The purpose of this study consisted of the characterization of the region which is systematically affected by intense rainfalls with serious damage to its economy. The period studied was from 1944 through 1990 (data were provided by DNAEE - Brasilia). The longest period possible was used for the interannual scale, whereas on the seasonal scale the typification and the variability of rain precipitation were studied for the rainy (6 months) and for the dry season (6 months) Different statistical parameters were employed. Relation of rainfall to the Southern Oscillation (SO) was studied on the interannual scale