Rising concentration of greenhouse gases may have significant consequences for the global climate with highest effects in human life and agricultural sectors. Therefore, forecast of climate changes in future is essential. The main goal of this research, is simulating daily precipitation and the temperature for the near (2021-2050) and far (2070-2099) future. The most common method of developing climate scenarios for quantitative impact assessments is using results from AOGCM experiments. Each AOGCMs has different simulation of the future. AOGCM models typically divide the atmosphere and ocean into a horizontal grid with a horizontal resolution of 2° to 4° latitude and longitude, with 10 to 20 layers in the vertical. So, there is need to a method for obtaining high-resolution climate or climate change information from relatively coarse-resolution global climate models (GCMs). Because of the uncertainties in GCM models and according to recent studies in many areas in the world, multimodel ensembles are believed to provide the most robust climate change information. The first step after getting the GCMs output is, getting the value of variables at the station. So, we need to an interpolation method to interpolate between variables value in GCMs. Towards to do that, we use IDW (Inverse Distance Weighting). The next step is forming a multimodel ensemble. and the problem is how to weight each GCM. In this research, we considered four weighting approaches 1. REA, 2. Raisenen method, 3. MOTP, and 4. the equally weighting approach. Each approaches assesses GCMs performance upon the some criterions and weights the GCMs. The observed data for climate variables in the Zayandeh-Roud River Basin for 2001-2009 are used to compare each multimodel. Better simulation the synthetic data for 2001-2009, respect to observed data, chooses the best weighting method. for forming a multimodel to simulate the temperature and the precipitation in near and far futures, we used the chosen weighting approach. The synthetic minimum and maximum temperature for near and far futures increased in whole the year but that’s different for precipitation. Although precipitation will decrease in both future periods, it’s not the same in whole the year. It incrased in summer and decreased in winter. Keywords: Climate Change, AOGCM, Weighting Method, Multimodel Ensemble, IDW