Climate change, especially changing precipitation patterns, is a challenging reality that affects different sectors of society, including the agricultural sector, which is highly dependent on the weather. This study aimed to predict drought conditions in future periods and compare current water consumption patterns and net water demand of 10 crops in five villages of Kohgiluyeh and Boyer-Ahmad province. To model climate change, daily data of minimum temperature, maximum temperature, precipitation, and sunny hours during the period (1986-2022) of the Yasuj and Gachsaran stations were collected from the provincial meteorological organization. Based on these data, the current water consumption pattern was estimated and net water demand of these products was calculated according to the climate of the province. To study drought and change rainfall patterns, three general circulation models that simulate precipitation well in most regions of the country were simulated by the LARS-WG model, then the drought profile was calculated using the ZimaSPI graphic function in MATLAB software. The results of monthly and annual precipitation patterns showed that precipitation in the studied area increases in the coming years, The results of monthly precipitation distribution indicate a decrease in winter precipitation and an increase in precipitation in spring and early autumn, which is often out of reach as the flood. Drought index analysis also indicates an increase in drought continuity and more occurrence of mild droughts. According to the results of precipitation and drought, the irrigation requirements in 5 villages and dryland and irrigated wheat, rainfed and irrigated barley, corn, corn, forage maize, watermelon, potato, onion, alfalfa, clover, and rice were investigated. Four scenarios including an unchanged level of access to water and a reduction of water quota of 10, 20, and 30 percent were used to investigate farmers' behavior. The study of changing water availability scenarios showed that the net water requirement was significantly lower compared to the water consumption pattern. The highest difference was observed in water requirement and amount of water consumed with 298% per rice and the lowest difference in water requirement and water use in clover (13%).