Climate change is characterized by observing changes in temperature and rainfall pattern. CPA is used order to detect whether any changes have occurred on a series of time ordered data. Present study deals with detection of change in the mean of a process in historical monthly temperature data using CPA for each districts of Tamil Nadu for the period of 1901 to 2002. The analysis of CPA shows that the districts in Tamil Nadu are exhibits changes in temperature over the years. Descriptive statistics and trend analysis revealed that maximum variation observed at Chennai and almost all the districts shows month wise significant trend.