2 min readBengaluruMay 16, 2026 03:29 PM IST
The Southwest monsoon marked an early arrival this year over some areas of the southwest and southeast Bay of Bengal, Nicobar islands, and Southeast Arabian Sea, the India Meteorological Department (IMD) announced on Saturday.
“The southwest monsoon has advanced into some parts of the southeast Arabian Sea, southwest and southeast Bay of Bengal, many parts of the Andaman Sea, the entire Nicobar Islands, and some parts of the Andaman Islands, including Sri Vijaya Puram, on May 16,” the IMD said.
This year’s monsoon onset over these regions is early by at least six days compared to normal.
The onset for this region was marked even earlier, on May 13, in 2025 (see table). As per the IMD’s monsoon onset schedule, the normal date for the monsoon onset over the south Andaman Sea, Port Blair in the Andaman and Nicobar islands, is May 22.
There has been an increase in rainfall activity during the past two days over the Nicobar Islands, the Andaman Sea, and the neighbourhood areas. In addition, the strengthening of the westerly winds and the desired Outgoing Longwave Radiation values, indicating the presence of convective cloud mass — all of which are the key criteria for declaring the monsoon onset.
The Met department also shared that conditions are favourable for further advancement of the southwest monsoon into some more parts of the southeast Arabian Sea, southwest and southeast Bay of Bengal, remaining parts of the Andaman Islands and Andaman Sea, and some parts of the east-central Bay of Bengal during the next few days.
The monsoon onset over Kerala is most likely on May 26, marking the commencement of the four-month monsoon season this year.
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The onset over the Andaman Sea, Bay of Bengal during 2019-2026
