Abstract
The onset and termination of the rainy season shape the planning and operation of water resources systems. Thus, we identify the onset and termination in Central Chile (32–40°S) from 1960 to 2021 based on the occurrence of frequent wet spells (consecutive days with rainfall ≥1 mm). The method yields a latitudinal gradient on both the onset and termination dates consistent with the latitudinal variation of annual precipitation. We report robust shortening trends for the rainy season north of 35°S over the last 30 years (up to 7 weeks per decade), primarily due to a delay in the onset date. Between 1990 and 2021, the number of wet spells exhibited a significant negative trend north of 35°S and a significant negative trend in the average precipitation per wet spell in 32–40°S. The changes in precipitation timing and the significant decline in precipitation observed in Central Chile are then affecting the current water infrastructure.