Withdrawal of the Southwest Monsoon: How Does IMD Determine When the Monsoon Retreats from India?
The withdrawal of the southwest monsoon has begun over India. On 19 September 2026, the India Meteorological Department (IMD) declared the withdrawal of the southwest monsoon from some parts of West Rajasthan, marking the beginning of the seasonal retreat of the monsoon. The arrival of the southwest monsoon is one of the most closely watched weather events in India. But its departure is equally important. The withdrawal of the monsoon marks a major transition in India's atmospheric circulation, gradually bringing an end to the southwest monsoon season and preparing the atmosphere for the post-monsoon season. But how does the India Meteorological Department determine that the southwest monsoon has started withdrawing? Is a reduction in rainfall alone enough? Not by itself. IMD uses a set of meteorological and synoptic criteria to identify the beginning of withdrawal and then monitors the progressive retreat of the monsoon across the country. With the southwest monsoon begi...