The annual rainfall or the seasonal rainfall during the southwest monsoon season (June to September), which contributes about 70-90 % of the total rainfall over most parts of the country, averaged over India as a whole for the period 1875-2021 has not shown any trend. However, the summer monsoon precipitation (June to September) averaged over India has declined by around 6% from 1951 to 2015, with notable decreases over the Indo-Gangetic Plains and the Western Ghats.
Since 1951, central India has experienced significant rising trends in the frequency and the magnitude of Heavy rainfall (≥100 mm) events and significant decreasing trend in the frequency of moderate rainfall (≥5 mm to 100mm) events resulting in no trend in the mean rainfall over the region. India. On the other hand, west coast of India and Northeast India experienced increasing trends in the intensity of the heavy rainfall and there was no significant trend in the frequency of the heavy rainfall events.