The transition of monsoonal onset is often demarcated by distinct variation of different meteorological parameters, namely, wind-speed, wind direction, Relative humidity and Air Temperature. In fact, with the change in regional and global climate, the specific variation of these parameters can be used for monsoon-transitional diagnostic benchmark. The present research work is based on analysis of selected climatic parameters in the deltaic zone of Thanjavur to track their distinct variability to evaluate possible monsoonal transition, which plays a crucial role in updating agro-almanac to suit the contemporary climatic variations.The study involved use of IOT-based automated weather station located at PRIST University campus of Thanjavur, recorded at an hourly periodicity. The air temperature and humidity showed a distinct higher in morning hours and lower in afternoon hours during pre-monsoon phase (i.e., July-Aug), in comparison to monsoonal phase (i.e., Aug-Sept.), whereas the wind velocity showed just the opposite trend and the transitional time is found to be between 6:00 Hr to 10:00 Hr. Dominant wind direction has been observed to have a northern twist during noon hours and southern twist during afternoon and night hours during July-August, compared to August-September, although during both phase, it remained predominantly westerly.