Extreme rainfall variability and trends in the district of Ouedeme, municipality of Glazoue (Benin)

This study aims to assess the extreme rainfall variability and trends in Ouedeme district, Glazoue municipality, Benin. Rainfall fluctuations, droughts, and floods pose major risks to food crops, mainly yams and rice, threatening food security and local agricultural systems’ resilience. The research is based on daily rainfall data from Savè synoptic station, covering 1961 to 2020. Seven ETCCDI climate indices (including PTOT, JP, SDII, P10, P20, PX1J, and CDD) have been used to quantify the intensity, frequency, and variability of extreme events. Statistical methods (mean, standard deviation, Lamb index) and software tools such as Excel have been used to process data and identify trends. The findings reveal that average annual precipitation amounts to 1,180 mm (±235 mm), with an overall downward trend. Also, while the mean number of rainy days is 82 (±11 days), the daily intensity (SDII) is 11 mm/day (±1 mm), both decreasing. However, a slight increase in heavy rainfall days (P10: 36 days ±7) and a moderate increase in very heavy rainfall days (P20: 18 days ±4) have been observed. Furthermore, consecutive dry days (CDD) are up to 34 days (±4), highlighting a trend towards more frequent dry spells. Overall, 32 of the 60 years analyzed had a deficit, compared to 28 with a surplus, reflecting significant interannual variability. Results highlight increased climate variability, with more frequent dry spells and intense rainfall, affecting crop cycles directly. Farmers’ adaptation strategies (early sowing, crop rotation, etc.) remain limited by insufficient resources and infrastructure. Improved water management and technical support are crucial to strengthening agricultural resilience to climate extremes.