The analysis of changing characteristics of monsoon rainfall in an urban catchment is crucial for planning urban flood mitigation measures and optimal water resource management. This study analysed the changing trends and patterns in monsoon rainfall in an urban district located in the south Indian peninsula. The study area being qualified as a smart city demands a detailed understanding on the occurrence of historical high intensity rainfall for future water resources management. The long-term rainfall time series (120 years from 1901 to 2020) was analyzed considering decadal, 5 years and yearly sub series using a more recent innovative trend pivot analysis method (ITPAM) as well as conventional methods such as the Mann-Kendall and Modified Mann-Kendall tests. The statistical analysis of annual and seasonal rainfall data (120 years) revealed that the mean annual rainfall varied between 3469 mm and 3009 mm with predominant monsoon rainfall concentrated in 3 months or less. The spatial variability of annual rainfall depicted the eastern part of the study area receiving maximum rainfall (highly localized). The study demonstrates the advantage of risk graph in ITPAM for identifying drastic variations in trend and extreme events. The study also suggests investigating short period rainfall data (yearly) at a local scale for capturing high intensity rainfall as compared to decadal coarse resolution rainfall data (state scale or country scale). This is important if the result of rainfall analysis is used for planning flood mitigation in highly urbanized smart cities.