Average annual precipitation -1,150 to 1,525 mm, increasing from north to south. Maximum precipitation is in winter and in spring, decreasing gradually through summer to autumn except for a moderate increase in midsummer. Average annual temperature -16 to 20 C, increasing from north to south. On the uplands shallow wells, cisterns, ponds and rural water systems are the main sources of water for domestic use and livestock. Shallow wells provide small quantities of water, but deep wells in underlying sand and gravel yield large quantities.
Most steams are small and flow intermittently.
They flow most of the time in winter and in spring but only during and immediately after storms in summer and in autumn. Most of the soils are Udalfs. They are deep, medium textured soils that have a thermic temperature regime, an udic moisture regime, and mixed mineralogy. Cherrybark oak and Shumard oak are widely distributed. Yellowpoplar, white ash, cottonwood, and black walnut are important species on the flood plains.