So far, several models have been proposed for estimating different climate parameters, but due to the lack of valid and long-term data in some meteorological stations, some models have been difficult to use. The SIMETAV V.1.0 model has been developed in cooperation with the University of California Davis and the Water Resources Authority of California in 2005. The SIMETAW model is a new and innovative tool for the estimation of applied water evapotranspiration (ETAW). SIMETAW simulation model is presented to estimate potential evapotranspiration and also estimate the net amount of water required for irrigation (ETaw). In addition, using this model, you can simulate daily meteorological data from meteorological data. The simulation of daily weather information where there are only monthly averages is a great tool for filling out lost data. In this research, Simetaw simulation model predicts different climate parameters such as solar radiation, minimum and maximum temperature, wind speed, dew point, precipitation and evapotranspiration potential in four different semi-arid climate zones (Mashhad). Dry (Bandar Abbas), moderate and humid (Ramsar) and Mediterranean (Sanandaj) during the years (1967-2017). The results of these studies showed that SIMETAW model has high ability to simulate climate variables and has the highest model accuracy in precipitation simulation (R2 = 0.998) and maximum temperature (R2 = 0.997) for semi-arid climate (Mashhad) , Dew point (R2 = 0.998) for temperate and humid climate (Ramsar), for radiation (R2 = 0.998) and wind speed (R2 = 0.9) for Mediterranean climate (Sanandaj) and minimum temperature (R2 = 0.998) for warm and dry climates (Bandar Abbas).