The present research is aimed at analyzing rainfall pattern and classification to evaluate in district wise data in Tamilnadu and make possible the result in various seasons to understand the climate change. The dataset relates to monthly rainfall from various districts of Tamilnadu in the period of January to December in the Indian Metrological Department database. The time frame of the data pertaining to the present study is 2004-2010. The salient feature of this study is the application of Factor Analysis, K-means clustering and GIS (Geographical Information System) Map as data mining tools to explore the hidden pattern present in the dataset for each of the study periods. Factor analysis is applied first and the factor scores of extracted factors are used to find initial groups by k-means clustering algorithm. Finally, data mining tools are applied and the groups are identified as rainfall belonging to HR (High Rainfall), MR (Moderate Rainfall) and LR (Low Rainfall). The results of the present study indicate that Data Mining Tools can be used as a feasible tool for the analysis of large set of rainfall data.