Abstract: In the context of global climate warming and frequent extreme weather events, analyzing the spatiotemporal distribution characteristics and trends of regional rainfall is crucial for disaster prevention and mitigation. Based on the observed data of 4 119 rainfall stations in Guangdong Province from 2017 to 2021, this study utilized inverse distance weighting and GIS to analyze the spatiotemporal changes and formation mechanisms of rainfall in Guangdong Province. The results are as follows:① The annual precipitation ranged from 1420.9 to 1993.6 mm, showing an intermittent upward trend. 2019 had the highest rainfall in the last five years, while 2020 and 2021 were rare consecutive drought years. ② The distribution of rainfall throughout the year was uneven, with heavy rainfall concentrated in the summer, accounting for 49.06% of the annual precipitation, followed by spring, autumn, and winter. The pre-monsoon period from April to June was dominated by frontal rain, while the post-monsoon period from July to September was characterized by tropical cyclone rain and convective rain. The period from October to March of the following year was the dry season. ③ Spatially, the distribution of rainfall showed that the western and central parts of Guangdong Province, as well as the northern edge of the Pearl River Delta, had higher rainfall, while the eastern and northeastern mountainous areas had less rainfall. ④ Short-duration heavy rainfall of 1 hour mainly occurred in summer and was most active between 17:00 and 19:00. In terms of spatial distribution, it was most frequent in the southern coastal plain area, followed by the northern mountainous region which also posed risks of geological disasters induced by heavy rainfall. Observations of rainfall exceeding 100 mm in 1 hour were mainly concentrated in the Qingyuan-Fogang area. These findings provide valuable references for disaster defense against heavy rainfall-induced hazards in Guangdong Province.