Above normal rainfall likely over entire S Asia region, including India, in June-Sept

Most parts of South Asia, including India, will see above normal rainfall during southwest monsoon season (June-September) while maximum temperatures over the central parts of the region and most areas in the southern parts are likely to be normal to below normal, the Consensus Outlook Statement for South Asia Summer Monsoon Season said on Wednesday.

The statement was released by M Ravichandran, secretary, ministry of earth sciences (MoES).

Above normal minimum temperatures are most likely over most parts of South Asia all of monsoon season, except some isolated areas of south-eastern part of the region where normal minimum temperatures are most likely.

“The seasonal maximum temperatures are most likely to be above normal over most areas of the northern, eastern, and northeastern parts of the region, as well as some areas in the southern parts. However, maximum temperatures over the central parts of the region and most areas in the southern parts are likely to be normal to below normal,” the statement said.

On April 15, the India Meteorological Department (IMD) predicted that monsoon rainfall during June to September, over the country is likely to be “above normal” at 105% of long period average (LPA) with a model error of ± 5%.

The private MET forecaster, Skymet Weather, had forecast a “normal” monsoon at about 102% of the LPA, with an error margin of 5%.

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The regional climate outlook for the 2025 southwest monsoon season over South Asia has been collaboratively developed by all nine National Meteorological and Hydrological Services (NMHSs) of South Asia with the support from international experts at the 31st session of the South Asian Climate Outlook Forum (SASCOF-31) being held in Pune.

The process involved an expert assessment of the prevailing global climate conditions, national level forecasts and forecasts from different climate forecasting agencies around the world.

“The northern hemisphere winter and spring snow cover extent has a general inverse relationship with the subsequent summer monsoon rainfall over South Asia. The NH winter and spring snow cover areas during January to March 2025 were below normal. The snow cover area during January and March respectively, was 4th and 6th lowest ever recorded during the past 59 years,” the statement said.

These projections from southwestern monsoon are made based on El Nino Southern Oscillation (ENSO); Indian Ocean Dipole; tropical Atlantic Sea surface temperatures, Eurasian land heating, among others. The relative impact of all these parameters needs to be considered to determine the expected state of the monsoon over the region, which is implicitly considered by the dynamical climate models that underpin the present outlook.

The ENSO is one of the global-scale climate phenomena that has a robust inverse association with the year-to-year variability of the monsoon over South Asia.

Currently,neutral ENSO conditions are prevailing over the equatorial Pacific region. The latest forecasts from various coupled global models indicate that the neutral ENSO conditions are likely to continue during the upcoming monsoon season.

In addition to ENSO, other factors such as the Indian Ocean Dipole (IOD) also influence the South Asian southwest monsoon. A positive (negative) IOD is in general associated with a stronger (weaker) than normal southwest monsoon over the region.

At present, neutral IOD conditions are prevailing over the Indian Ocean. The recent forecasts from coupled global models suggest that the neutral IOD conditions are likely to continue during the southwest monsoon season.