Abstarct: Abstract Iran, due to its unique geographical location and climatic diversity, is clearly affected by climate change. The significant increase in temperature and irregular changes in precipitation patterns have brought serious challenges to the country's vital resources, including water reserves and agricultural production. This research aimed to evaluate the performance of CMIP6 climate models in simulating temperature (minimum and maximum) and precipitation at 31 selected synoptic stations during the historical period of 1970 to 2014. The performance of 32 minimum temperature models, 32 maximum temperature models, and 51 precipitation models was evaluated using statistical indices including the coefficient of determination (R2), absolute normalized mean bias deviation (ANMBD), normalized root mean square error (NRMSE), normalized Nash-Sutcliffe efficiency coefficient (NNSE), and normalized Kling-Gupta efficiency coefficient (NKGE), and weighted using the entropy method. The final ranking of the models was conducted through the Simple Additive Weighting (SAW) method and several Multi-Criteria Decision-Making (MCDM) methods (WAT, CP, CGT, and TOPSIS), and finally, Group Decision Making (GDM) identified the superior models. The results of the Group Decision Making indicated that the ACCESS-CM2, FGOALS-g3, and MIROC-ES2H models were identified as the superior models in simulating minimum temperature, the INM-CM5-0 model in simulating maximum temperature, and the IITM-ESM and MIROC-ES2L models in simulating precipitation. To analyze future changes, an ensemble model consisting of the top three models for each station was developed baxsed on the weights assigned to the models from the Brekke et al (2012). method, and its data were downscaled under two scenarios, SSP245 and SSP585, for the future period of 2025 to 2069 using the Change Factor method. The trend analysis of minimum and maximum temperatures showed that in both scenarios, temperature increases are predicted across all selected stations, with the magnitude of the increase being greater in the SSP585 scenario compared to SSP245. In contrast, the trend of precipitation changes did not show a consistent pattern across the stations and scenarios. This research, while providing a comprehensive evaluation of climate models, offers a picture of future temperature and precipitation changes in selected regions of Iran.