All climatic elements, whether singly or in combination, affect crop and animal production. The climatic elements of greatest significance to agricultural production in Kenya are rainfall, temperature and evapotranspiration. The balance between rainfall and evapotranspiration is particularly important. Characterization of an area based on climatic parameters relevant to agriculture (i.e., agro-climatic) is a useful practical exercise. The resulting agroclimatic zones indicate which areas are climatically suitable for different crops. Additional information on the length and intensity of the rainy and dry periods and on soil characteristics is necessary to designate agroclimatic zones.