Abstract: To investigate the spatial and temporal distribution characteristics of short-term extreme rainstorms in Fujian, the 1-h, 3-h and 6-h annual maximum precipitation during daytime and nighttime at 121 meteorological stations were used to characterize the extreme rainstorms from 1974 to 2023. The spatial and temporal distribution characteristics of short-term extreme rainfall were analyzed by the Mann-Kendall test and the regional L-moments method. Results show that Fujian can be divided into 4 hydrometeorological homogeneous regions, most of the annual maximum precipitation series are optimally fitted with the Generalized Extreme Value (GEV) distribution and the L-moments method has a higher accuracy compared with the normal moment method. The short-term rainstorm extreme values in Fujian decreased from 1970 s to 2000 s and the growth trend was significant after 2000 s. Extremes values in high altitude areas have structured from nighttime to daytime, while the rest of the areas have increased both daytime and nighttime. Meanwhile, the range of extreme rainstorms at high-altitude stations was expanding annually, stations located on the southern slopes had an increased probability of suffering extreme rainstorms at night, and stations located on the northern slopes had a shorter duration of extreme rainstorms over time. Influenced by the complex factors involving topography and geomorphology, changes in weather systems and so on, the short-term extreme rainstorm volume in Fujian generally decreased from the east coast to the west inland. The large-value areas were distributed along the coast, Southern areas and the mountainous areas of Western Fujian. The probability of short-term extreme rainstorms along the coast of northern Fujian was greater in nighttime compared to daytime. The 1-h and 3-h short-term extreme rainstorms along the coasts of central and southern Fujian were lower in amount at night. The probability of short-term extreme rainstorms during the daytime was higher and the duration of precipitation was longer in the interior of western Fujian. The short-term extreme rainstorms along the central Fujian mountains were consistently lower in both amount and probability. These patterns are governed by sea surface temperature anomalies (enhancing southwestern moisture transport via western Pacific warming). Diurnal wind regimes (dominated by sea breeze convergence with orographic lift during daytime versus land breeze-low-level jet coupling at night). Synergistic triggering from spatial coupling between frontogenesis processes and high-θse energy tongues—where terrain forcing critically amplifies nocturnal rainfall. Diurnal moisture divergence-convergence phases, driven by wind variations, are further regulated by sea breeze circulation and tropical systems.