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Environment & Ecology July 03, 2026 5 min read Daily brief · #14 of 36

‘Strong’ El Nino during June-Sept, below-normal rain over Indian subcontinent : WMO

Meteorological agencies have forecast a 'strong' El Niño event for the June–September 2026 period — the critical southwest monsoon window for India. The Indi...

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What Happened

  • Meteorological agencies have forecast a 'strong' El Niño event for the June–September 2026 period — the critical southwest monsoon window for India.
  • The India Meteorological Department (IMD) has lowered its seasonal rainfall outlook to approximately 90% of the Long Period Average (LPA), placing the 2026 monsoon in the below-normal category.
  • India recorded a 40% rainfall deficit in June 2026, with the shortfall most acute in central, eastern, and northeastern India, where over three-quarters of districts reported deficient or negligible rainfall.
  • An 84% probability of below-normal or deficient seasonal rainfall has been estimated for the 2026 monsoon season.
  • The forecast threatens kharif crop sowing, groundwater recharge, reservoir levels, hydropower generation, and rural incomes — with approximately 200 vulnerable districts placed under contingency agricultural planning.

Static Topic Bridges

El Niño-Southern Oscillation (ENSO): Mechanism and Classification

ENSO (El Niño-Southern Oscillation) is the dominant interannual climate variability signal on Earth, originating in the tropical Pacific Ocean. It operates through coupled ocean-atmosphere feedback: anomalous sea surface temperature (SST) warming (El Niño) or cooling (La Niña) in the central and eastern Pacific drives large-scale shifts in atmospheric circulation, affecting rainfall patterns globally.

  • El Niño (warm phase): Anomalous warming of SSTs in the central/eastern Pacific weakens trade winds, suppresses convection over the Maritime Continent and Indian subcontinent, and shifts the Walker Circulation eastward — reducing Indian monsoon rainfall.
  • La Niña (cool phase): Opposite pattern; strengthened trade winds, enhanced convection over South Asia — typically boosts Indian monsoon.
  • Southern Oscillation Index (SOI): Atmospheric measure of ENSO — calculated as the standardised pressure difference between Darwin (Australia) and Tahiti. Negative SOI = El Niño; positive SOI = La Niña.
  • El Niño classification by strength: Weak, Moderate, Strong, and Very Strong (e.g., 1997–98 and 2015–16 events were Very Strong/Super El Niño).
  • ENSO recurs every 2–7 years; strong El Niño events have historically been associated with 20–40% rainfall deficits over India.

Connection to this news: The 2026 event is classified as 'strong,' placing it in a historically high-impact category for Indian monsoon suppression — explaining the 40% June deficit and the IMD's below-normal seasonal forecast.

Indian Ocean Dipole (IOD): The Modifier

The Indian Ocean Dipole (IOD) is an ocean-atmosphere climate mode in the Indian Ocean, defined by the east-west gradient in SSTs. A positive IOD (warmer western Indian Ocean/Arabian Sea, cooler eastern Indian Ocean) enhances moisture transport into the Indian subcontinent and can partially offset El Niño's suppressive effect on the monsoon.

  • Positive IOD years that counteracted El Niño and produced near-normal or above-normal Indian monsoon rainfall: 1983, 1994, 1997.
  • Negative IOD combined with El Niño: worst-case scenario for Indian rainfall — as in 2002 (26% deficit) and 2015 (14% deficit).
  • IOD peaks in October; its phase during the key July–September monsoon months is most consequential for seasonal totals.
  • IOD is measured by the Dipole Mode Index (DMI): positive DMI = positive IOD.

Connection to this news: The 2026 monsoon deficit persisting despite the season's progress suggests the IOD is not providing sufficient counterbalancing enhancement, compounding the El Niño impact.

IMD's Long Range Forecasting System

The India Meteorological Department (IMD) issues Long Range Forecasts (LRF) for the southwest monsoon in two stages: Stage 1 in April (seasonal outlook) and Stage 2 in June (updated forecast with monsoon onset data). Forecasts are expressed as a percentage of the Long Period Average (LPA).

  • IMD's Long Period Average (LPA) for India's annual rainfall: approximately 87 cm (based on 1971–2020 data).
  • Monsoon rainfall categories: Above normal (>104% LPA), Normal (96–104%), Below normal (90–96%), Deficient (<90%).
  • The 2026 Stage 2 forecast was approximately 90% of LPA — the boundary between below-normal and deficient.
  • IMD uses a suite of models including the Multi-Model Ensemble (MME) system and the Statistical Ensemble Forecasting System (SEFS).
  • IMD coordinates with WMO's Global Producing Centres (GPCs) for ENSO monitoring.

Connection to this news: IMD's revised forecast to 90% of LPA — coupled with the 40% June deficit already observed — is the scientific basis for the government's multi-ministry drought preparedness review.

Impact on Food Security and Agricultural Vulnerability

India's food security rests significantly on the southwest monsoon. Kharif crops (rice, maize, jowar, bajra, cotton, soybean, sugarcane) are sown in June–July and harvested in September–October; they are rain-fed for the most part, as irrigation infrastructure covers less than half of the net sown area.

  • Approximately 60% of India's farmers depend on rain-fed agriculture with limited or no irrigation access.
  • A below-normal monsoon typically reduces kharif foodgrain output, raises food price inflation (especially for pulses, coarse cereals, and vegetables), and depresses rural consumption and incomes.
  • Reservoir levels in major dams — which supply both irrigation and drinking water — are critically affected by monsoon performance; hydropower generation falls correspondingly.
  • The government's district-level contingency crop planning involves recommending drought-tolerant, shorter-duration crop varieties when sowing is delayed beyond threshold dates.
  • IMD and the Ministry of Agriculture coordinate to issue advisories for each agro-climatic zone as the monsoon evolves.

Connection to this news: The 200 districts flagged for El Niño vulnerability represent India's most rain-dependent agricultural zones; the strong El Niño forecast triggers pre-emptive crop planning to minimise output loss and rural distress.

Key Facts & Data

  • 2026 El Niño classification: Strong
  • India's June 2026 monsoon deficit: approximately 40% below normal
  • IMD seasonal forecast for 2026: approximately 90% of LPA (below-normal)
  • Probability of below-normal or deficient 2026 seasonal rainfall: 84%
  • Long Period Average (LPA) for Indian annual rainfall: approximately 87 cm (1971–2020 baseline)
  • Rainfall classification thresholds: Above Normal >104% LPA; Normal 96–104%; Below Normal 90–96%; Deficient <90%
  • Number of vulnerable districts: approximately 200
  • Major El Niño drought years for India: 2002 (~26% deficit), 2009 (~23% deficit), 2015 (~14% deficit)
  • Positive IOD years that offset El Niño: 1983, 1994, 1997
  • ENSO recurrence cycle: every 2–7 years
  • Kharif sowing window: June–July; harvest: September–October
  • Rain-fed agriculture share: approximately 60% of net sown area
  • IMD LRF Stage 1: April; Stage 2: June (updated with onset data)
On this page
  1. What Happened
  2. Static Topic Bridges
  3. El Niño-Southern Oscillation (ENSO): Mechanism and Classification
  4. Indian Ocean Dipole (IOD): The Modifier
  5. IMD's Long Range Forecasting System
  6. Impact on Food Security and Agricultural Vulnerability
  7. Key Facts & Data
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