Monsoon to be ‘above normal’ this year: IMD

India can expect above-normal monsoon season this year, the India Meteorological Department (IMD) announced in its long-range forecast on Tuesday, predicting rainfall to be around 105% of the long-period average in what holds significant implication for an increasingly heat-stressed nation and its economy.

The forecast, which comes with a model error margin of ±5%, is somewhat more optimistic than the 102% “normal rainfall” prediction made by private forecaster Skymet Weather last week. The June-September rainy season delivers nearly 70% of India’s annual rainfall and remains vital for the economy.

The LPA for the monsoon season based on the 1971-2020 period stands at 87cm. According to IMD’s probability assessment, there is a 33% chance of “above normal” monsoon (105-110% of LPA), 26% chance of “excess” monsoon (>110%), 30% chance of “normal” monsoon (96-104%), 9% chance of “below normal” monsoon (90-95%), and only 2% probability of a “deficient” monsoon (<90%).

About 51% of India’s farmed area, accounting for 40% of agricultural production, relies entirely on rainfall.

To be sure, IMD does not necessarily get these predictions right and the overall rainfall figure in itself can mask wide disparities across regions.

HT’s analysis of IMD’s first forecasts since 2001 shows their statistical accuracy has been worse than predicting a coin toss, with the forecast differing from actual performance by more than five percentage points in 14 of the past 24 years. This gives IMD’s initial forecasts an accuracy of just 42%, although the agency’s performance has improved in recent years.

Last year, India experienced “above normal” monsoon at 108% of LPA, when IMD predicted 106% of the LPA with a model error of ±5%. The year before, during 2023, an El Niño year, IMD predicted “normal” monsoon at 96% of LPA, but actual rainfall was below normal at 94%. Both years were, however, within the agency’s error margin.

Private forecaster Skymet Weather last week predicted a more conservative “normal” monsoon at about 102% of LPA, with a 5% error margin.

Several climate patterns support a favourable monsoon outlook this year, IMD said in its briefing. Currently, Pacific Ocean conditions are in a neutral El Nino state, though atmospheric circulation patterns resemble those typically seen during La Nina conditions—a scenario that historically benefits Indian monsoons.

These neutral conditions are expected to continue throughout the monsoon season.

Similarly, the Indian Ocean is showing neutral dipole patterns, which will likely persist through the southwest monsoon period.

Another positive indicator is the below-normal snow cover observed across the Northern Hemisphere and Eurasia during January through March 2025.

M Mohapatra, director general of IMD, explained why that helps the monsoon: “Monsoon has a negative relationship with snow cover. Higher the snow cover area, less is the rainfall. This is because higher snow cover means colder landmass. Cold landmass will lead to a weak monsoon current because monsoon is nothing but cross-equatorial flow of wind,” he said.

The spatial distribution of rainfall is expected to vary across the country. IMD’s forecast suggests above-normal seasonal rainfall across most of India, except some areas in Northwest India especially Jammu and Kashmir, northeast India, parts of east India especially Bihar, and south peninsular India particularly Tamil Nadu, where below-normal precipitation is likely.

When questioned about the trend of below-normal rainfall in northeastern India during recent monsoon seasons, M Ravichandran, secretary at the ministry of earth sciences, pointed to evolving climate patterns: “During the past one decade we are seeing the west-east dipole change. The Thar desert region, traditionally arid, is recording more rain while northeast, which traditionally records good rainfall, is seeing a minor reduction in rainfall quantum.”

What will also be keenly watched is the progress of the monsoon, which enters the Kerala coast at the end of June and makes a gradual, albeit often staggered, march across the country. The IMD last month predicted a scorching summer. Most parts of the country should expect above-normal day and night temperatures between April and June, with northwest and east India likely to experience an increased number of heat wave days, the agency said on March 31.

While the hot weather season typically brings 4 to 7 heat wave days, this year could see 6 to 10 such days.

For the monsoon forecast, the agency uses multi-model ensemble forecasting systems based on coupled global climate models from different climate prediction centres, including IMD’s Monsoon Mission Climate Forecast system.

Climate experts also caution that even with accurate headline rainfall figures, increasing geographical and temporal variations in rainfall patterns—likely due to climate change—make economic planning based solely on overall rainfall predictions increasingly challenging.

IMD will issue updated monsoon forecasts in the last week of May, which should provide greater clarity on regional variations and potential economic impacts as the season approaches.

Abhishek Jha contributed to this report