Climate change is a general term that describes climatic discontinuity and rupture. In order to study temperature changes in Hamadan, temperature fluctuations in a statistical period of fifty years (1952-2002) have been investigated. According to a survey conducted in 1973, a sudden drop in the minimum, and a sudden rise in the maximum, temperature were observed. According to the Mann Kendall test, there are significant changes in the three parameters of minimum, maximum and average temperature, including the decreasing trend observed in 1962, and this negative trend continued until 1992, and this year thereafter, an increasing trend of temperature can be observed. It should be noted that the maximum spring temperature is an exception, since in the year 1992 it is the beginning of cooling season. On the minimum temperature chart, the falling trend starts from 1957 and continues until 1974. The result is that the year 1992 is the beginning of a period of increasing temperature and climate change in Hamedan, and the temperature rise is 0.55 degrees averagely, 0.79 ° C at minimum temperature and 0.3 ° C at maximum temperature.