Rainfed agriculture is the primary source of food production in sub-Saharan Africa (SSA). Recommendations for agricultural practices in the area are based upon agronomic crop research. However the research may not have been able to ‘sample’ the longer-term rain variability due to short, three- to five-year research durations and the short-term rainfall variations that occurred during the studies. Consequently, farmers cannot be adequately advised to cope with weather-induced risks over the longer-term. The study demonstrates that crop growth simulation models and weather generators can be used to assess the value of the outputs and analyze climate risk in a high potential maize production area in Kenya. An examination of the relative importance of radiation, water availability, and temperature at various maize growth stages corresponded well with crop physiological research presented within the article.