Global Characterization of Precipitation Peaks in the Seasonal Cycle

Abstract Precipitation seasonality is commonly described using wet and dry periods, but this framework can obscure multiple rainfall maxima within a rainy season. Here we introduce a global framework for identifying the number of precipitation peaks (NPP) during rainy periods from daily precipitation using optimal harmonic seasonal fits and reproducible peak‐selection criteria. We find that multimodal precipitation seasonality is widespread, covering approximately 60% of global land. Most multimodal regions have two or three peaks, whereas higher‐order regimes occur mainly in weakly seasonal dry or wet regions, where the seasonal cycle is poorly defined and more sensitive to precipitation variability. Detected peaks are generally separated by seasonal‐scale intervals. Temporal evolution of NPP demonstrates weak long‐term trends, with larger temporal variability concentrated in regions with relatively weak seasonality. These results provide a systematic global characterization of precipitation peak structure and establish NPP as a complementary metric for diagnosing precipitation seasonality.