New Delhi, May 13, 2025 — The Southwest Monsoon (SWM) is expected to advance into the South Andaman Sea, Nicobar Islands, and parts of the southeast Bay of Bengal by May 13, 2025, according to the latest update from the India Meteorological Department (IMD). This signals an early arrival of the monsoon season, ahead of its normal schedule.
On May 10, the IMD had forecasted that the monsoon may begin over Kerala by May 27, which is four days earlier than the typical onset date of June 1. Earlier, on April 15, the agency had predicted that the 2025 monsoon season is likely to deliver above-normal to excess rainfall across the country.
The expected early movement of the monsoon is being supported by the development of a low-pressure area in the Bay of Bengal. While this system may or may not intensify into a tropical cyclone, it is likely to assist the initial push of monsoon winds into the Bay of Bengal and the Andaman region. However, it is not expected to play a major role in the later onset over Kerala.
In recent weeks, widespread thunderstorm activity has been observed across many regions of India, bringing rainfall, hail, and temporary relief from heatwave conditions. These thunderstorms have been the result of active western disturbances and multiple upper air cyclonic circulations, which have created elongated low-pressure zones known as troughs. The IMD reported that one such western disturbance was present in the mid-troposphere as of May 11.
This storm activity is likely to continue in different parts of the country until at least May 15. Though intense thunderstorms in April and May can sometimes interfere with the land heating process necessary for the monsoon’s timely arrival, current indications suggest that they will not disrupt the onset of the monsoon.
Additionally, the IMD has forecasted that the monsoon will continue its progress over the southern Arabian Sea, Maldives and Comorin region, more areas of the South Bay of Bengal, and the entire Andaman & Nicobar Islands during the next 4 to 5 days. Some parts of the central Bay of Bengal are also expected to come under the monsoon’s influence during this period.
With the early signs pointing towards a timely and robust monsoon, agricultural sectors, water management authorities, and millions of citizens across the country are now closely watching its progress, hopeful for a season that brings both relief and replenishment.