Abstract This study has used monthly rainfalls from Regional Climate Models (RCMs) experiments conducted in the frame work of the COrdinated Regional Downscaled EXperiment (CORDEX) project for historical and future periods. The deriving General Climate Models (GCMs) are obtained from Coupled Model Inter-comparison project phase 5 (CMIP5). Rainfalls from RCMs for the historical period, the two scenarios (i.e. Representative Concentration Pathway (RCP) scenarios representing radiative forcing of 4.5 m/W 2 (RCP4.5) and 8.5 m/W 2 (RCP8.5)) and Climate Research Unit (CRU) are used to determine precipitation concentration index (PCI), standardized precipitation index (SPI), and trend. The PCI, SPI, and trend derived from CRU and Historical Ensemble Mean (HEM) rainfalls are used to (1) assess the fidelity of the models in capturing observed spatiotemporal characteristics of rainfall over East Africa (EA) and (2) assess the relative change in the pattern of rainfall extremes and trends from the two scenario projections. From CRU and HEM-based SPI, the normal rainfall years are about 62–80% and 62–71% of the time of the historical period (1951–2005) during March-May (MAM) and September-December (SOND) respectively. The spatial dipole pattern captured by CRU and HEM is visible in the projections under the two scenarios implying that both radiative forcing are not expected to alter current rainfall regime over EA. In addition, normal rainfall is expected to occur for 62–68% and 65–72% of the time of the projection period (2006–2100) during MAM and SOND respectively. The projected rainfall shows wetting trend during MAM in contrast to the historical observations of dry trends over much of EA.