The southwest monsoon is likely to withdraw from the entire country around October 15, placing this year’s retreat among the earliest in recent years, while the northeast monsoon is expected to begin over southern India, according to the India Meteorological Department and Skymet Weather Services.
The IMD’s latest extended-range forecast said conditions were expected to become favourable for the complete withdrawal of the southwest monsoon during October 15-21. It also forecast the onset of the northeast monsoon over south peninsular India during the same period.
The transition is expected to bring scattered to fairly widespread rainfall across most parts of peninsular India and the east coast. The IMD has also forecast isolated heavy rainfall over coastal Andhra Pradesh, Odisha, Tamil Nadu, south interior Karnataka and Kerala for a few days during the onset period.
Rainfall is expected to remain above normal over south peninsular India during the week, while northwest, eastern and northeastern India are likely to receive below-normal rainfall, according to the forecast. The differing regional outlook means that the end of the southwest monsoon will not mark a uniform end to wet weather across the country.
GP Sharma, president of Skymet Weather Services, said the southwest monsoon could retreat from the south peninsula and the remaining parts of central and eastern India by October 13. Only Mizoram and Tripura may remain under its influence at that stage, with withdrawal from the entire country potentially completed within the following 48 hours.
The monsoon began retreating on September 19 and has already withdrawn from northern, western and central India. The current withdrawal line passes through Supaul, Ranchi, Sundargarh, Bargarh, Bijapur, Hyderabad, Belagavi and Panaji. Sharma said rainfall activity was continuing over Bihar, West Bengal, Odisha and parts of the northeast despite the near-complete withdrawal on the western side.
The withdrawal of the southwest monsoon and the onset of the northeast monsoon could occur simultaneously or within 48 hours of each other, Sharma said. He explained that the retreat is considered complete once the withdrawal line reaches around 15 degrees north latitude over the peninsula and the monsoon flow vacates the remaining parts of the country.
Rainfall over the extreme southern peninsula, below 15 degrees north latitude, can begin before the IMD formally declares the onset of the northeast monsoon. This has already occurred during the current season, according to Sharma.
The retreat remains a variable process. Sharma said it typically takes four to six weeks but can stall abruptly, accelerate or progress according to schedule. In 2019, withdrawal began on October 9 and concluded on October 16. During the La Niña years from 2020 to 2022, the retreat was delayed by several days.
If the IMD formally declares the southwest monsoon withdrawn around October 15, the date would match the earliest completion dates recorded over the past decade and a half. Withdrawal was completed on October 15 in 2024, October 16 in 2025 and October 19 in 2023. Between 2011 and 2021, the earliest completion was recorded in 2019, on October 16, while the retreat was delayed until October 28 in 2020 and October 25 in 2021.
The IMD’s next extended-range assessments and the position of the withdrawal line will determine whether the forecast transition occurs within the projected October 15-21 window.
