For the 30 stations considered, the analysis of the homogenized data indicates that the 1918-2023 time series are not stationary. They all exhibit breaks, with the year 1969 being the most frequent. Precipitation decreases toward the north, with average rainfall around 300 mm. At the seasonal scale, July, August, and September are the key months of the rainy season, both before and after the break. Annual rainfall, meanwhile, has shown a declining trend, with more or less pronounced deficits between pre-break and post-break averages, except at the Bakel station, which shows an increasing trend.In short, a significant interannual variability, marked by a succession of surplus and deficit years, is currently observed in the middle Senegal River basin: the 1918-1969 period remains notably wet, a dry period occurs from 1972 until the 1994-2003 decade, followed by a slight increase in precipitation that does not conform to the stations’ normal values from 1981-2010. The analysis of river discharge highlights an increase in flows despite the decrease in rainfall. However, rainfall-runoff modeling is necessary To describe better the hydrological functioning of the basin and to develop a water resources management model for this vulnerable area. on the other hand, the increased upstream rainfall variability observed since last year threatens the regularity of inflows, making adaptive reservoir management crucial. Moreover, a rainfall–runoff modelling approach would help better describe the hydrological functioning of the basin and predict the future of the hydrosystem.