Recent Climate Change in Benin Since the Mid‐20th Century: Spatiotemporal Trends, Regime Shifts, and Extremes in Precipitation and Temperature

ABSTRACT

This study investigates long‐term climate change in Benin over the period 1950–2024, focusing on precipitation and temperature variability, trends, breakpoints, and extreme events. The results reveal that annual precipitation ranges from 1034 mm in Kandi to 1320 mm in Cotonou, with overall declining trends (−0.4 to −4.5 mm/year). A recovery in rainfall is observed in Kandi after 2000 (trend = +2.73 mm/year). Annual Precipitation Concentration Index (PCI) values indicate generally moderate rainfall concentration, except in northern Benin, where irregular temporal distribution is observed (PCI≈20 in Kandi), accompanied by a slight reduction in drought occurrence, from 16.5% during 1950–1999 to 14% during 2000–2024. Extreme precipitation indices reveal increasing trends in the number of consecutive dry days (0.013–0.149 days/year) and decreasing trends in the number of consecutive wet days (−0.007 to −0.039 days/year). Seasonal analyses comparing the 1950–1999 and 2000–2024 periods highlight delays in the onset of the rainy season in central regions (about 10 days in Bohicon and 2 days in Savè), while the length of the rainy season remains relatively stable. In contrast, an extension of the rainy season is observed in Cotonou (+16 days) and Kandi (+7 days), whereas a shortening is detected in Parakou (−13 days) and Natitingou (−17 days). Most precipitation breakpoints were detected during the 1960s and 1970s. Mean annual temperature averages approximately 27.5°C nationwide, with higher maximum temperatures in the north (up to 33.6°C) and higher minimum temperatures in the south (around 24.4°C in Cotonou). Over the past half‐century, mean, maximum, and minimum temperatures have increased by approximately 0.88°C, 1.03°C, and 1.04°C, respectively. Breakpoints vary depending on the station and variable. Significant warming trends are observed across all stations, reaching up to +0.029°C/year. Seasonal analyses also indicate a significant increase in heat wave frequency (e.g., from 0.134 to 0.333 days/year). Overall, these findings emphasize the urgent need for adaptation measures to mitigate the growing impacts of climate change on agriculture and water resources in Benin.