干旱是长期缺水影响自然资源和环境的最广泛的水文气象模式。然而，它在不同地区有明显不同的特征。泰米尔纳德邦遭受着包括干旱在内的各种灾难。一般来说，降雨量偏离长期平均值仍然是广泛采用的干旱强度评估指标。这一指标的应用受到其依赖平均值的固有性质的严重限制。因此，克服这些限制的标准化程序成为一种基本需求。此外，近年来降雨的稳定性一直不稳定，因此，为了了解多年降雨的稳定性，使用了降水比(PR)。为了进一步了解泰米尔纳德邦南部地区的干旱气候学，使用了标准化降水指数(SPI)。研究了三十年(1981-2010)，覆盖了七个地点。在1981-90年期间，大多数地区的降雨是稳定的，此后，稳定性逐渐下降，这证实了近十年的极端天气。 SPI had an annual range from +2.69 to -4.94 while Monsoon period had +2.41 to -3.43 and +2.69 to -3.14 respectively for Southwest and Northeast monsoon seasons. As per SPI index, Southern zone is prone to moderate drought followed by severe and extreme drought category. Among the periods studied (Annual, SWM and NEM) number of moderate drought occurrences had no much variation while in severe and extreme drought category, variations could be observed. In particular, during NEM period there was almost no occurrence of extreme drought.