Fire weather severity in southern Africa is increasing faster and more extensively in the late than in the early dry season

Background In African savannas, the most intense fires occur during the late dry season, when fuel availability is high and atmospheric relative humidity low. The Fire Weather Index (FWI) system has been used to measure the effort required for fire suppression and explore the impact of climate on fires.Aims This study assesses trends in FWI system indices from 1979 to 2022 and their influence on burned area (BA).Methods We employed the Theil-Sen slope estimator and contextual Mann-Kendall test to evaluate the presence of significant trends in FWI system indices during the early dry season (EDS) and late dry season (LDS), and assessed how trends in BA depend on fire weather.Key results We found distinct patterns in fire weather trends between the EDS and LDS, the LDS showing more widespread areas of increasing trends. However, only 28% of the regression analyses showed significant relationships with BA, suggesting a moderate influence of the FWI system on BA interannual variance.Conclusions Fire weather severity is increasing faster and more extensively during the LDS than the EDS. Additional factors play a significant role in shaping BA trends. Proactively managing anthropogenic fires during the moister EDS can help mitigate fire intensity, reduce emissions and support biodiversity conservation efforts.