Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli Smith (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscan Burkholder (Xapf) is the most serious biotic constraint of common bean (Phaseolus vulgaris L.) production. Variables temperature and moisture are dominant climate factors that affect common bean growth as well as the development of CBB epidemics. Two sets of experiments were conducted in the Plant Pathology Laboratory of Haramaya University) to assess the effect of temperature and moisture on the resistance level of common bean in 2014 and 2015. In the first experiment, two common bean varieties (Gofta and Mexican 142) were inoculated with two bacterial strains (Xap and Xapf) and a control were incubated at four temperature levels (28°C, 30°C, 32°C and 34°C) in growth chambers. In the second experiment, three-soil moisture levels (100%, 75% and 50%) were employed to that of experiment one. The treatment combinations were arranged in factorial completely randomized design (CRD) in the growth chambers for both series of experiments. The disease rating was significantly (P<0.05) affected by common bean varieties and temperature levels at 17 days after inoculation (DAI). Higher disease rating was recorded on the variety Mexican 142 than on Gofta. The highest (1.75) mean disease rating was recorded at 28°C and the lowest (1.44) at 34°C. The mean disease ratings differed significantly among the moisture levels. The highest (2.01) mean disease rating was recorded from 75% moisture content, while the lowest (1.80) disease rating was obtained from 50% moisture content. The results of these series of experiments indicated that climate change effects above optimum level would not be favorable for CBB development in the arid and semi-arid agro ecologies unless new bacterial strains adapted to the drought tolerant common beans in the area.