The Indian monsoon, a seasonal juggernaut delivering roughly 70 percent of the nation’s annual rainfall between June and September, has been both a boon and a bane for India over the past decade (2015–2025). As the lifeblood of an agrarian economy supporting nearly 700 million people, the southwest monsoon dictates agricultural output, water security, and economic stability. Its variability, amplified by climate change, has led to a rollercoaster of floods, droughts, and uneven rainfall, impacting everything from rural livelihoods to urban infrastructure.
The India Meteorological Department (IMD), entrusted with forecasting this vital phenomenon, has leveraged advanced models and technology to improve predictions, yet its record reveals a blend of triumphs and stumbles. This piece explores the monsoon’s impact on India from 2015 to 2025 and evaluates the IMD’s forecasting effectiveness, pinpointing its successes and failures with data-driven clarity.
Over the past ten years, the monsoon’s erratic behavior has left indelible marks on India’s landscape and economy. In 2015, rainfall was 14 percent below the long-period average (LPA) of 87 cm, marking a deficient year that crippled agricultural production. States like Maharashtra and Uttar Pradesh faced severe droughts, with food-grain output dropping by nearly 5 percent, inflating food prices and straining rural economies.
The preceding year, 2014, was similarly dry at 12 percent below LPA, compounding distress. However, 2016 brought relief with a near-normal monsoon at 97 percent of LPA, bolstering Kharif crop yields and recharging groundwater in rain-fed regions. The 2017 season, at 95 percent of LPA, maintained this stability, supporting rice and pulse production critical for food security.
The 2018 monsoon, at 109 percent of LPA, flipped the script, delivering above-normal rainfall that triggered devastating floods in Kerala, where over 2,300 mm of rain fell, claiming over 400 lives and displacing millions. Uneven distribution left parts of Rajasthan parched, highlighting the monsoon’s spatial variability. In 2019, rainfall soared to 110 percent of LPA, the highest in 25 years, but its late retreat until October—the latest since 1961—caused floods in Bihar and Karnataka, with damages estimated at $1.5 billion.
The 2020 and 2021 seasons were normal, at 99 percent and 96 percent of LPA, respectively, providing a brief respite for farmers but masking regional disparities, such as dry spells in central India and excessive rain along coasts. The 2022 monsoon, at 106 percent of LPA, saw 55 percent of India’s tehsils receive over 10 percent more rain than the 1982–2011 baseline, leading to flash floods in Assam and Gujarat. In 2023, El Niño-driven deficits brought rainfall to 94 percent of LPA, impacting Rabi crop prospects in the monsoon core zone.
The 2024 season, at 108 percent of LPA, a four-year high, boosted hydropower and groundwater but overwhelmed urban centers like Mumbai and Chennai with flooding. Preliminary data for 2025 suggests another above-normal season at 106 percent of LPA, with early heavy rainfall in Kerala and Karnataka, though final figures are pending.
The monsoon’s impacts are profound. Normal or above-normal seasons, like 2016 and 2020, enhance agricultural GDP, which constitutes about 20 percent of India’s economy, and stabilize food prices by ensuring robust Kharif harvests. Excessive rainfall, as in 2018 and 2019, causes floods that disrupt infrastructure, displace communities, and incur billions in losses. In 2022, hydro-meteorological disasters, primarily monsoon-driven floods, accounted for 83 percent of Asia’s natural hazards, with India bearing significant economic costs.
Deficient years like 2015 deplete groundwater, particularly in irrigation-heavy states like Punjab, and drive inflation as food supplies dwindle. Climate change has intensified these extremes, with a 40 percent rise in extreme rainfall events in Assam and a 10 percent increase in monsoon rainfall across 55 percent of tehsils from 2012 to 2022. Urban areas, grappling with poor drainage and land-use changes, face heightened flood risks, as seen in Bengaluru and Delhi, which oscillated between deficits and deluges.
The IMD’s forecasting, critical for agricultural planning and disaster preparedness, has evolved significantly. Since 2012, the Monsoon Mission Coupled Forecasting System (MMCFS) and Statistical Ensemble Forecasting System (SEFS) have reduced the average absolute error from 7.94 percent of LPA (1995–2006) to 5.95 percent (2007–2018), with further gains post-2018.
The IMD issues a two-stage long-range forecast (LRF): an initial prediction in April and an update in June, incorporating global climate signals like El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Himalayan snow cover. A forecast is deemed successful if actual rainfall falls within the ±5 percent error margin and correctly categorizes the monsoon as deficient (below 90 percent of LPA), normal (96–104 percent), or above-normal (above 104 percent).
From 2015 to 2024, the IMD accurately predicted six monsoons: 2016, 2017, 2018, 2020, 2021, and 2024. In 2016, it forecasted 106 percent of LPA, with actual rainfall at 97 percent, within the error margin. The 2017 prediction of 96 percent closely matched the 95 percent outcome. For 2018, the IMD’s 97 percent forecast underestimated the 109 percent reality but stayed within the margin.
The 2020 and 2021 forecasts of 100 percent and 98 percent aligned with actuals of 99 percent and 96 percent, respectively. In 2024, the IMD’s 106 percent prediction was nearly exact, with rainfall at 108 percent. These successes reflect advancements in dynamical models, denser radar networks, and integration of global climate data, particularly La Niña and positive IOD signals.
The IMD faltered in four years: 2015, 2019, 2022, and 2023. In 2015, it predicted 93 percent of LPA but saw 86 percent, missing the deficient category and underestimating drought severity. The 2019 forecast of 96 percent failed to anticipate the 110 percent deluge, misjudging its intensity and late retreat. In 2022, the 103 percent prediction underestimated the 106 percent outcome, particularly the severity of wet spells.
The 2023 forecast of 96 percent overestimated rainfall, which fell to 94 percent due to an unexpectedly strong El Niño, disrupting agricultural planning. These misses, averaging a 7 percent error, highlight challenges in predicting extreme events and spatial variations, such as Mumbai’s rainfall, where the IMD was inaccurate for 40 percent of July days in 2024.
The IMD’s limitations stem from the monsoon’s complexity and climate change-induced unpredictability. While statistical models assume historical patterns, rapid shifts in ENSO or IOD can skew outcomes, as seen in 2023. Dynamical models, though improving, struggle with micro-climatic variations, particularly in rain-shadow regions like the Deccan Plateau.
Despite these challenges, the IMD’s role in reducing cyclone-related deaths—down from 10,000 in 1999 to zero in 2020–2024—demonstrates its growing capability. To enhance monsoon forecasts, experts advocate for higher-resolution models (e.g., 12-km grids under the MoES’ ACROSS scheme) and better integration of local data.
In sum, the past decade’s monsoons have swung between prosperity and peril, shaping India’s agricultural and economic landscape. The IMD’s six accurate forecasts underscore its progress, but four failures reveal gaps in tackling extreme variability. As climate change intensifies monsoon unpredictability, refining models and local-level forecasting will be crucial to mitigate the impacts of this vital yet volatile phenomenon.