Iraq suffers the continuing lack of water resources in generdwether it is surface or underearth water or rain. The study of rain has got the utmost importance in order to the rain direction in Iraq and in Mosul in particular and what it will be in future. It also shows the wet as well as the dry seasons and the possibility of expecting them and expecting their quantities in order to invest them and to keep this vital resource The research deals with predict the wet and dry rainy seasons in Mosul using (SPI) Standardized precipitation index extracted from conversion of Gamma distribution to standardized normal distribution , depending on data of monthly rain amounts for 1940-2013 . Results showed existence of 31 wet rainy seasons , and 42 dry rainy seasons for the whole time of study which is 73 rainy seasons. Results of rainy seasons prediction for the time 2014-2023 showed five wet rainy seasons and five dry rainy seasons , although the general trend of rain in Mosul station refer to declines with time
