Changes in spatio-temporal rainfall patterns have an effect on the hydrological behavior of river basins, the magnitude of the effects depending among others on the physiographic basin characteristics. To assess climate and discharge fluctuations, a visualization tool was developed as a contribution to exploratory data analysis. The tool combined statistical tests of hydro-climatological variables with physiographic basin characteristics. Test results agree with previous studies and suggested a relationship between rainfall, discharge and mean date of the annual maximum discharge on the one the hand and lithology, altitude and west to east positioning of the basins on the other hand. The visualization tool capable of combining the statistical test results with the geologic and topographic configuration of the study area and allowed a reflection on the hydro-climatological as well as spatio-temporal behavior of meso-scale basins by means of exploratory data analysis.