Abstract:Based on the hourly precipitation data of 125 national stations from 2005 to 2018, the spatio-temporal distribution characteristics of hourly precipitation in Yunnan were studied. The results show that the spatial distributions of annual total precipitation, different duration precipitation, extremely severe precipitation and diurnal variation of precipitation are significantly different. The annual rainfall increases from northwest to south, and intensity enhances from north to south. The rainfall duration in west is more than in the east, and that in south is slightly more than in the north. The annual rainfall is affected commonly by rainfall duration and intensity. The influence of duration is stronger than that of intensity, especially in northwest Yunnan, but the rainfall in northeast Yunnan has better correlation with intensity. Most areas of Yunnan receive more rainfall at night than in the daytime, especially in northeast and northern margin of Yunnan. The diurnal variation of precipitation features a single peak at night in the northern part, a single peak in early morning in the western edge, double peaks at night and in the afternoon in the central and southern part, but the occurrence times of major peak and secondary peak are different in southern part. The precipitation southern Yunnan is mainly from the short and medium duration precipitations, while that in the north is mainly from long and ultra-long duration precipitations. Times of short-time severe precipitation increase from northwest to southeast, and its annual change has an increasing trend. Its daily distribution shows a significant single peak from dusk to night, but extreme short-time severe precipitation is more likely to occur in the early hours of the morning. These spatio-temporal characteristics of hourly precipitation largely represent the characteristics of the low-latitude plateau. The spatial distribution difference of hourly precipitation characteristics is related to the weather system. The low-value weather system mostly affects the central and northern part of the low-latitude plateau, while the southern part is mostly affected by tropical weather system. Moreover, the topography is complex, and the local thermal conditions are greatly distinct. All these factors contribute to the significant differences in the spatio-temporal distribution characteristics of hourly precipitation in this region.