The eastern periphery of the Tibetan Plateau (EPTP), which connects the Tibetan Plateau in the west and the Sichuan Basin in the east, is a typical area with steep terrain. The performance of the ERA5 reanalysis data in revealing the regional rainfall events (RREs) over the EPTP was evaluated by conducting a comparison with the rain‐gauge data. The results showed that the ERA5 precipitation could capture the general spatiotemporal features of the evolution of the observed RREs with spatial correlation coefficients greater than 0.8, but obvious bias still existed. The rainfall frequency was generally greater and the rainfall intensity was weaker in the ERA5 precipitation from the Tibetan Plateau to the Sichuan Basin, with the rainfall amount being smaller over the EPTP and Sichuan Basin and larger over the eastern Tibetan Plateau. ERA5 precipitation tended to start earlier and end later relative to the RREs in the gauge data. During the RREs, the distribution of the precipitation intensity in ERA5 was weaker and more uniform than that of the gauge records, and the spatial ranges were larger, which responded well to the higher rainfall frequency but weaker intensity in ERA5 when compared with the gauge data. These findings remind us that attention should be paid when using reanalysis precipitation, especially over complex terrain such as that of the EPTP. Moreover, the incorrect timing of the ERA5 precipitation and the underestimation of the precipitation intensity indicated that problems still exist in the state‐of‐the‐art model system.

The southeastern extension of the Tibetan Plateau (SETP) is distributed by the typical longitudinal mountains and has unique climate characteristics and significant regional differences. The diurnal cycles of rainfall amount, frequency, and intensity over the SETP in the warm seasons (May-September) were investigated using high-density hourly station rainfall data and the possible mechanisms were discussed by analysing the ERA5 reanalysis and satellite data. The largest amounts of rainfall appeared on the southern and western margins of the SETP, and the rainfall amount was relatively small at the higher elevations of the SETP. Located at the southern margins of the SETP, the adjacent western (Reg_W) and eastern (Reg_E) regions presented a similar rainfall amount, frequency, and intensity, but the diurnal features of the two regions were quite different. The rainfall amount, frequency, and intensity had dominant peaks in the late afternoon in Reg_W, while in the early morning in Reg_E. A secondary peak in the early morning can be found in Reg_W. The diurnal features of the two regions were closely related with the low-level atmospheric conditions and the distribution of clouds. The enhanced convergence of the anomalous southerly winds and sufficient water vapour after midnight contributed to the nocturnal rainfall at the southern edge of the SETP. In the afternoon, the lower surface air temperature and more stable stratification in Reg_E, as compared with Reg_W, were relatively unfavourable for the occurrence of afternoon convection.