Temporal Variability and Trends of Rainfall, Temperature and Water Balance in Za-Kpota Municipality, Southern Benin, West Africa

Abstract

The municipality of Za-Kpota, located in southern Benin, is highly vulnerable to climate variability due to its strong dependence on rain-fed agriculture, which constitutes the main source of livelihood for local populations. This study aims to analyze the spatio-temporal variability of key climatic parameters in this municipality over the period 1993–2022. This study presents a retrospective analysis of long-term climatic data (1993–2022) obtained from the Bohicon synoptic station. The methodological approach is based on the analysis of long-term climatic time series, particularly rainfall and temperature data. Statistical analyses, including trend detection methods and the computation of climatic indices, were applied to characterize the temporal evolution and variability of the studied parameters. The results reveal a bimodal rainfall regime, characterized by two rainy seasons with a cumulative duration of approximately six months. Mean monthly temperatures range from 25.8 °C in August to 29.5 °C in March, with the highest temperatures recorded between February and April. This period is associated with increased evaporation and evapotranspiration, potentially reducing water availability in the study area. In addition, the climatic water balance indicates an overall annual deficit of −171.3 mm, despite significant surpluses observed between May and June (+279.8 mm), and secondary positive balances during September and October. These findings highlight the pronounced variability of climatic conditions in Za-Kpota and their potential impacts on water resources and agricultural systems. The study provides a robust scientific basis for the development of locally adapted climate change strategies and emphasizes the need to integrate climate information into territorial planning and sustainable agricultural development policies.