It is in order to understand the variability of climatic and hydrological factors and their impacts on the agro-pastoral activities of the populations living along the Upper Niger basin that we have written this article. The research focused on three sub-basins and the data obtained through services were collected and analyzed. At the end of the work, the study revealed that there are variations that impact flow rates, rainfall levels and yields, allowing an agricultural calendar to be established. The main results obtained during this research are as follows: The month of September is the month of heavy rains with the total rainfall amounts varying from 5090mm between (1922-1931) to 7547mm between (1962-1971) and the month June is the least rainy month when the rainfall totals range from 2476mm to 37,033mm. The year 1974 was the driest with rainfall amounts of 29.6mm in May. For the 1955-1984 observation series, the mean flow is 187.38 m³/s for the Milo River and 242.72 m³/s for the Niandan River. The statistical calculation gives an average of 235.67 m³/s for the first decade and 199.25 m³/s for the sixth decade.