The average annual precipitation in the province is 450 mm, which provide favorable conditions for plant growth. From climatic point of view, there are three types of climate in Ilam province : The mountainous areas of northern and northeastern of the province, including Ilam, Shirvan-chardavol, Eyvan and Malekshahi are relatively cold with long winters, the minimum temperature is -15 °c, with more than 500 mm of annual rainfall. The plain areas of western and southwestern, including Mehran and Dehloran are warm with 250 to 350 mm of annual rainfall, the maximum temperature is 45 °c . The middle regions of the province, including Abdanan and Darrehshahr are moderate and semi-warm. The minimum temperature during winter is -5 °c and maximum temperature is 45 °c during summer.