Average annual precipitation -375 to 750 mm. About three-fourths of the precipitation falls during the growing season. In the western part rainfall is adequate for range grasses but inadequate for cultivated crops, and in the central and eastern parts rainfall is marginal for both. High temperatures and high evaporation and transpiration rates in summer limit crop production. Only a few rivers and streams flow throughout the year.
Deep wells provide some water for irrigation and livestock and for domestic needs.
Most of the soils are Ustolls. They are stony and moderately fine textured and fine textured. These soils have a thermic temperature regime, an ustic moisture regime, and carbonatic or montmorillonitic mineralogy. Mid and short grasses and an abundance of low-growing woody plants characterize the vegetation in the west. Oaks in association with mid and tall grasses grow in the central and eastern parts.