The India Meteorological Department (IMD) on Thursday announced the onset of southwest monsoon over Kerala coast after its forecast of an “early onset” on May 26 failed to materialise.
“Conditions are favourable for further advance of southwest monsoon into some more parts of central Arabian Sea, entire Goa, parts of Maharashtra and Andhra Pradesh, Karnataka, Tamil Nadu, Bay of Bengal, Northeastern states during next 2-3 days,” according to a met department statement.
During the past two days, there are several factors such as increase in convective cloudiness over southeast Arabian sea and widespread rainfall with isolated heavy rainfall over Kerala which ‘satisfied conditions’ for declaring onset of monsoon, net department said.
Typically, the monsoon, after onset over the Kerala coast in early June, covers the entire country by July. These southwest monsoon rains, which accounts for around 75% of the country’s annual precipitation, gradually begins to recede from north India by mid-September.
Historical Benchmarks
Delay in monsoon onset is attributed to weak monsoon winds earlier. The delay in onset into the mainland has been despite its arrivals over the Andaman Sea and neighbouring areas on May 16, a week ahead of normal schedule.
The monsoon reached Kerala on June 8 in both 2016 and 2023. In contrast, it arrived early in the past two years, making landfall on May 30 in 2024 and May 24 in 2025. The earliest onset date recorded this century is May 18, 2004.
According to the Met Department, its operational forecasts of monsoon onset over Kerala during 2005-2025, were proved to be correct except in 2015. This year also the met department could not provide a correct forecast and it stated that the onset of monsoon is 3 days after the usual date of June 4.
Agricultural Impact
The adequate rainfall boosts hopes of a robust agriculture-sector output as Kharif crops — paddy, pulses, oilseed and coarse cereals —sowing start with the onset of rains. The monsoon rains also provide soil moisture for the winter (rabi) crops — wheat, oilseeds and pulses.
However, the met department lowered its forecast of “below-normal” southwest monsoon rainfall for June-September this year to 90% of the long-period average (LPA), implying that the coming monsoon could be the weakest since 2015.