Resumen
The interanual, seasonal fluctuations of precipitation in the S. Paulo State were analyzed. The meteorological data were collected by Departamento de Agua e Energia Eletrica (DAEE). These data comprise the years 1948 to 1988. The seasonal scale was studied to classify the precipitation and to understand the winter (six months) and summer (six months) variabilities. We have used different statistical parameters, such as mean, correlation, standard deviation. The interanual fluctuations were studied through the relation of the precipitation in S. Paulo State with South Oscillation (SO). Virtually all significant variations were associated with extreme phases of the SO. It has also been verified that the most important caracteristic of the SO effect is the persistence of weak precipitation anomalies for several months. Although statistically significant SO signal can be associated with either above or below normal precipitation.