What Happened
- Forecasters have flagged the possible development of a "Super El Niño" in 2026, comparable in intensity to the strong El Niño events of 1982, 1997, and 2015
- However, historical data shows that El Niño does not always directly translate to monsoon failure: the 1997 El Niño — one of the strongest on record — delivered a normal monsoon over India, indicating a tenuous one-to-one correlation
- The key moderating factor identified: the Indian Ocean Dipole (IOD) — a positive IOD can significantly offset El Niño's suppressive effect on the Indian summer monsoon
- Seasonal forecasts from ECMWF (European Centre for Medium-Range Weather Forecasts) and NCEP (USA) suggest the possible development of a positive IOD during the 2026 monsoon season
- Private forecaster Skymet has projected the 2026 monsoon at 94% of the Long Period Average (LPA) of 868.6 mm (June–September), with a 40% probability of below-normal rainfall — El Niño is expected to emerge (62% probability) by June–August 2026
- The Indian Meteorological Department (IMD) is expected to release its first official forecast later in April 2026
Static Topic Bridges
Indian Ocean Dipole (IOD) — Definition and Mechanism
The Indian Ocean Dipole (IOD) is an irregular oscillation of sea-surface temperatures (SSTs) in the Indian Ocean. In its positive phase, the western Indian Ocean becomes anomalously warmer and the eastern Indian Ocean (near Indonesia/Sumatra) becomes anomalously cooler. This east-west SST gradient alters atmospheric circulation — specifically the Walker circulation — driving increased rainfall over the western Indian Ocean region, including India.
- IOD is measured by the Dipole Mode Index (DMI): difference in SST anomalies between western equatorial Indian Ocean (50°E–70°E, 10°S–10°N) and southeastern equatorial Indian Ocean (90°E–110°E, 10°S–0°N)
- Positive IOD: warmer western Indian Ocean, cooler eastern Indian Ocean → stronger low-level westerly winds over the Indian Ocean → enhanced moisture transport to the Indian subcontinent → better monsoon rainfall
- Negative IOD: cooler western Indian Ocean, warmer eastern Indian Ocean → reduced moisture transport → monsoon deficits; also associated with droughts in eastern Africa and floods in southeastern Australia
- IOD events typically peak between July and November; they are distinct from but often correlated with ENSO (El Niño-Southern Oscillation) events in the Pacific
Connection to this news: A positive IOD in 2026 is the critical factor that could moderate the expected El Niño-driven monsoon deficit — as it did in 1997, when a positive IOD helped deliver a normal monsoon despite strong El Niño conditions.
El Niño-Southern Oscillation (ENSO) and India's Monsoon
El Niño refers to the periodic warming of sea-surface temperatures in the central and eastern equatorial Pacific Ocean. This warming disrupts the Walker circulation — a large-scale atmospheric circulation cell — causing the descending limb to shift over South Asia, suppressing convection and reducing moisture delivery to the Indian subcontinent. Historically, strong El Niño events are correlated with below-normal or deficient monsoons in India.
- Walker Circulation: low-level easterly winds across the equatorial Pacific → warm water piles up in the western Pacific (normal) → rising air, convection, rainfall over Indonesia/South Asia; during El Niño, this pattern reverses
- ENSO classification: El Niño (positive ENSO/warming); La Niña (negative ENSO/cooling); Neutral; classification threshold: ≥0.5°C anomaly in the Niño3.4 region (5°N–5°S, 120°W–170°W) for 5 consecutive overlapping 3-month periods
- India's monsoon correlation with El Niño: strong negative correlation exists but is not deterministic; approximately 60% of strong El Niño years have below-normal Indian monsoons
- Notable anomalies: 1997 (strong El Niño, normal Indian monsoon due to positive IOD); 2015 (strong El Niño, deficient monsoon — negative IOD compounded it)
- "Super El Niño": informal term for events exceeding +2.0°C anomaly; 1982–83 (+2.2°C), 1997–98 (+2.4°C), 2015–16 (+2.6°C) are the three strongest on record
Connection to this news: Forecasters project a 62% probability of an El Niño emerging by June–August 2026, with strength potentially comparable to the "Super El Niño" events — making the IOD phase the decisive factor for monsoon adequacy.
India's Southwest Monsoon — Agricultural and Economic Significance
The Indian Summer Monsoon (ISM) or Southwest Monsoon (June–September) accounts for approximately 70–80% of India's annual rainfall. It is the lifeline of Indian agriculture, particularly Kharif crops (paddy, maize, cotton, soybean, groundnut). Below-normal monsoon affects reservoir storage, groundwater recharge, Kharif crop output, food inflation, and rural incomes.
- Long Period Average (LPA): 868.6 mm (updated by IMD based on data for 1971–2020)
- Monsoon classification: excess (>110% LPA), above normal (105–110%), normal (96–104%), below normal (90–95%), deficient (<90%), large deficient (75–89%)
- IMD's official seasonal forecast: released in April (first stage) and May/June (second stage); IMD uses the Ensemble Model, Statistical Model, and coupled ocean-atmosphere models
- Kharif crops at risk from below-normal monsoon: paddy (about 60% of total rice crop), cotton, soybean, groundnut, kharif pulses (tur, moong)
- A 1% shortfall in monsoon rainfall can reduce agricultural GDP by approximately 0.3–0.5%; Kharif shortfalls typically push food inflation up by 0.5–1.0 percentage points within 2–3 months
Connection to this news: The 2026 monsoon outlook has direct implications for Kharif crop production, food inflation (a key input into RBI's CPI projections), rural distress, and overall agricultural GDP — making it a critical macroeconomic variable at this juncture.
IMD and Monsoon Forecasting Institutions
The Indian Meteorological Department (IMD), under the Ministry of Earth Sciences, is the nodal government agency for weather and climate forecasting in India. IMD releases official seasonal forecasts, cyclone warnings, and long-range forecasts. Private forecasters such as Skymet operate alongside IMD.
- IMD established: 1875 (headquarters: New Delhi; main offices in Pune, Mumbai, Chennai, Kolkata)
- IMD uses: ensemble dynamical models (global and regional), statistical models, ENSO/IOD state as predictors for seasonal forecasts
- Ministry of Earth Sciences (MoES): nodal ministry; also oversees IITM (Indian Institute of Tropical Meteorology, Pune) and NCMRWF (National Centre for Medium Range Weather Forecasting, Noida)
- Key forecasting benchmarks: April forecast (Stage 1) gives probability of above/below normal; May/June forecast (Stage 2) gives regional distribution
- El Niño monitoring: IMD monitors the Niño3.4 index (Pacific SST anomalies) and DMI (IOD) as leading indicators
Connection to this news: IMD's official April 2026 first-stage forecast — expected to be released later in the month — will be the authoritative assessment of monsoon prospects and will significantly influence government policy on food stocks, fertiliser allocation, and crop insurance activation.
Key Facts & Data
- LPA of India's southwest monsoon: 868.6 mm (June–September; 1971–2020 base period)
- Skymet 2026 monsoon forecast: 94% of LPA (below normal; ±5% error margin)
- Probability distribution (Skymet): 0% excess, 10% above normal, 20% normal, 40% below normal, 30% deficient
- El Niño emergence probability (June–August 2026): 62%
- Major El Niño years and India monsoon outcomes: 1982 (deficient), 1997 (normal — positive IOD offset), 2015 (deficient — negative IOD compounded)
- ENSO classification threshold: ≥0.5°C anomaly in Niño3.4 region for 5 consecutive 3-month periods
- IOD positive phase: warmer western Indian Ocean, cooler eastern Indian Ocean → better monsoon
- IOD negative phase: cooler western, warmer eastern → monsoon deficits
- IMD established: 1875; headquarters: New Delhi
- India's monsoon share of annual rainfall: 70–80% of total annual precipitation
- Monsoon failure impact: 1% rainfall shortfall → approximately 0.3–0.5% fall in agricultural GDP