The southwest monsoon is likely to begin over parts of the southern Bay of Bengal, Andaman Sea and Andaman and Nicobar Islands this weekend, the India Meteorological Department (IMD) said on Tuesday.

“Conditions have become favorable for the possible onset of southwest monsoon over parts of the south Bay of Bengal, Andaman Sea and Andaman and Nicobar Islands this weekend. An area of low pressure over southwest Bay of Bengal is located over the same area at 8.30 am today, May 12, 2026, with an associated cyclonic circulation extending to 4.5 km above mean sea level. It is likely to become more pronounced over the next year. 48 hours,” the IMD said.
But officials said they could not predict the onset of monsoon over Kerala immediately. “We hope to release the Kerala start forecast on or around May 15,” said M Mohapatra, Director General, IMD.
June 1 is the natural date for the onset of monsoon in Kerala. The monsoon later advances northward, usually in the form of storms, covering the entire country around 15 July.
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The monsoon usually advances over northeastern India around June 5. It advances over northeastern India simultaneously with Kerala when the Bay of Bengal monsoon arm is active.
The onset of the monsoon and rainfall amounts are particularly important this year because El Niño conditions are likely to develop during May-June and July.
In India, El Niño is associated with harsher summers and weaker monsoons. Monsoon rainfall over the country is likely to be below normal at 92% of the long period average (LPA) with a margin of error of +/- 5%, the IMD had forecast in April. The average seasonal rainfall over the country as a whole during the period 1971-2020 is 87 cm.
HT previously reported that ocean temperatures last April were the highest since a record warming spell in 2024, climate models have shown, with the world’s waters warming rapidly as a strong El Niño approaches.
The average global sea surface temperature (SST) in April was 21 degrees Celsius, the second-highest on record for the month, just below the record 21.04 degrees Celsius set in April 2024, when the oceans were in the midst of unprecedented heat, the Copernicus Climate Change Service (C3S) said in a forecast last week.
The IMD warned that heatwave conditions at a few places with severe heatwave conditions in isolated pockets are likely to prevail over western Rajasthan during the next six to seven days.
An isolated heatwave is also likely over eastern Rajasthan, neighboring central India, Gujarat and Maharashtra during the next four to five days.
Scattered heavy rains are also likely over Tamil Nadu, Puducherry, Karaikal, Kerala, Mahe and south interior Karnataka over the next four to five days.
The Ministry of Earth Sciences (MoES) on Tuesday launched two advanced weather forecasting products developed under the Ministry of Environment and Energy, with the aim of providing hyper-local, impact-based and AI-driven weather services across the country.
The two products launched include offering IMD’s first Artificial Intelligence (AI) based system in the form of AI-powered ‘Monsoon Progress Forecast over Different Parts of the Country’ and ‘High Spatial Resolution Rainfall Forecast for Uttar Pradesh’ as a pilot service.

