Abstract: This work presents a study of the rainfall in the east-center region of the Sao Paulo state (Brazil) during the summertime. Data from three meteorological stations (Campinas airport - KP; Guarulhos airport - GR; and Astromonical and Geophysics Institute of the Sao Paulo University - IAG) are used. The behaviour and distribution of the rainfall, as well as the synopic aspects are analyzed. A comparison between observed rainfall and rainfall predicted by ETA model (CPTEC) is done. It is intended to give a contribution for better understanding of the meteorological variables and their relations with different synoptic systems associated to them.