In this research air temperature characteristics of five meteorological stations located in the Hamedan region of Iran were analyzed. The main objective was to identify and assess the possible climate change of the region during the period 1980 to 2010. To this end, time series of the mean annual temperature were investigated using Mann-Kendall and Normalized Residual Mass Curve methods. The climatological stations were Hamedan, Ekbatan Dam, Dargazin, Nojeh and Varayaneh. The results showed that the Mann-Kendall and Normalized Residual Mass Curve tests were similar on detection of the trends. The mean annual temperatures of stations with the exception of Varayaneh and Darghazin showed significant rapid increasing trends. This study illustrates the identical results of the two different tests on climate change identification and more importantly a significant warming at the majority of stations in the region. These results provide useful information for long term planning in water management of the region.