This study investigates impact of the climate change on temperature and precipitation parameters for the Torogh Dam watershed using a weighted combination of four AOGCM models of the sixth phase of climate change models (CMIP6) under three scenarios: SSP1-2.6, SSP3-7.0, and SSP5-8.5 over the basic period (1993-2012) and the four future periods (2021-2040, 2041-2060, 2061-2080 and 2081-2100). Initially, in order to evaluate the performance of the models, five statistical measures, as well as correlation coefficient, were used to compare the results of the historical period of the models with the observation period of the selected stations as well as the watershed average. After ensuring the ability of all four models to simulate precipitation and temperature parameters in the study watershed, in order to reduce uncertainty, the results of all four models in the base period were combined using MOTP weighting method and the weight of each model was obtained. Finally, based on the amount of weights obtained for each model, the results of all four models for future periods were combined with each other. The study results show a sinusoidal trend of precipitation changes under ssp5-8.5 scenario in different periods, which includes an increase in precipitation in two periods of 2021-2040 and 2061-2080 and a decrease in two periods of 2041-2060 and 2081-2100. While the amount of precipitation under ssp1-2.6 scenario will not change significantly for the first period, but will increase for the two periods of 2041-2060 and 2061-2080 and will decrease for the last period. For ssp3-7.0 scenario, this includes a decrease in precipitation for all time periods except the first period, which will not be changed significantly. In terms of temperature changes, the predictions show an increase in minimum and maximum temperature under all scenarios and in all periods compared to the base period. For ssp3-7.0 and ssp5-8.5 scenarios, this includes increasing each period compared to the previous period.