The objective of this study was evaluates the impact of climate change on seasonal rainfall patterns over Bale Highlands by using climate data from National Meteorology Agency and downscaling Coordinated Regional Climate Downscaling Experiment (Cordex) output data from cordex Africa. In order to estimate the climate change signal scenarios of rainfall and temperature were developed for periods of 30 years (2011 to 2100). The outputs GCM model for the RCP4.5 and RCP8.5 emission scenarios were used to produce the future scenarios. Instat V3.7 software was governed for this study. The sample size for this study was 768 respondents randomly selected. Results of R 2=0.58 for temperature over study area which shows that there is a good correlation between downscaled and observed data. The study shows that there is an overall increasing trend in seasonal maximum and minimum temperatures and decreasing of seasonal rainfall from the base period. The onset, cessation and Length of Growing Periods in both Belg and Kiremt season shifts from the base years. Observational data, GCM date and farmer's perception showed similar result and there is a shift of seasons over Bale highlands form 2 days to dekade. During Kiremt season there was decreasing of LGP from 109 to 101. Similarly, the LGP of Belg was reduced from 84 days to 48 days at the end of 21 st century. The onset of Belg season at the end of 21st century will shifts to May. The anticipated shift of Kiremt season will merging to Bega (dry season) with this the author recommended the local farmers or any concerned body uses this information which is significant amount of rainfall require appropriate acclimatization strategies to minimize risks, increase crop productivity, and avert food insecurity of the area.