Season’s end: On the India Meteorological Department forecasts, rainfall deficit

The India Meteorological Department (IMD) issues two forecasts — in April and May — before the monsoon. Both unambiguously pointed to a dry monsoon — confidence boosted by global unanimity that one of the strongest El Niño ever was in the offing — and the consequential question was, ‘How bad?’ It turns out that the IMD’s forecast of ‘below normal’ rain (90% to 95% of average) was conservative. This was surprising, given that its models pointed to ‘deficient’ rains (below 90%). On September 30, when India’s monsoon tally ended, the IMD announced 759 mm across the country, 87% of the normal 869 mm. El Niño years, when the Central Equatorial Pacific warms and suppresses monsoon rains, test a weather department’s mettle because predicting the extent of the shortfall is challenging. It is perplexing why the agency opted for ‘below normal’ rainfall when it could have warned of a ‘deficiency’ and claimed accuracy. As of now, the IMD can only claim technical victory because the final number sits within the 4%-5% error window. However, at a disaggregated level, the IMD’s struggle with getting magnitude right is far more glaring. June got 65% of its normal, far drier than the 92% forecast. July, expected to be below 94%, ended up with 1% point more rain. August came in at 84% of the LPA, in line with the “below 94%” forecast. September at 92.4% finished a little above the forecast of ‘below 91%.’ The IMD expected a ‘normal’ monsoon in the northeast, which then recorded its driest since 1901, or 26% short. The south peninsula ran 23% short. Central and north-west India — tipped to fall below normal — finished close to predictions, driven by ocean conditions and Western disturbances.Climate change makes this more complicated. Western disturbances, extra-tropical rain-bearing systems, have been bringing more rain to India in the monsoon months, while southern India seems more vulnerable to El Niño-triggered volatility. This is reflected in kharif sowing. On July 10, kharif sowing trailed last year’s by 16%; by early September the gap had narrowed to under 2%. Karnataka has declared drought in well over a 100 taluks and Maharashtra in 265 of 358, though the national deficit of about 12% is below the Centre’s 20% threshold for an ‘agricultural drought.’ The IMD expects El Niño to strengthen and bring below normal rain over most of the country from October to December, threatening soil moisture and reservoir recharge. The Cabinet has lifted wheat’s support price by ₹25 a quintal and mustard’s by ₹413, nudging diversification. Given the consequences of IMD’s forecasts, it should improve its sub-regional forecast systems and not shy from being the bearer of ill-news, if needed. Published - October 02, 2026 12:11 am IST