El Nino developing: Rainfall in India may see 11-year low in 2026
El Niño conditions are developing in the equatorial Pacific ahead of India's Southwest Monsoon season (June–September 2026), with IMD assigning a 92% probabi...
What Happened
- El Niño conditions are developing in the equatorial Pacific ahead of India's Southwest Monsoon season (June–September 2026), with IMD assigning a 92% probability to El Niño materialising during the monsoon window.
- The IMD's revised forecast of 90% of the Long Period Average (LPA) represents the lowest projected rainfall in approximately 11 years, recalling the 2014–15 El Niño drought cycle.
- Beginning June, 11 states are expected to face heatwave advisories as the dual pressure of below-normal rainfall and elevated temperatures converges on the pre-monsoon and early monsoon period.
- Northeast India is the sole major region forecast to receive adequate rainfall; Central, South Peninsular, and Northwest India face the sharpest moisture deficits.
- The development follows the end of the 2020–2023 triple-dip La Niña, which typically precedes a stronger ENSO swing toward El Niño.
Static Topic Bridges
El Niño — Onset, Development, and Monsoon Suppression
El Niño events develop when sea surface temperatures (SSTs) in the central and eastern equatorial Pacific warm by 0.5°C or more above the 30-year average for at least five consecutive overlapping three-month periods (as tracked by the Oceanic Niño Index). The warming weakens the trade winds and disrupts the Walker Circulation — the east-west atmospheric conveyor belt — reducing evaporation and moisture transport toward the Indian subcontinent.
- El Niño onset is monitored using the Niño 3.4 region (5°N–5°S, 120°W–170°W); a +0.5°C anomaly sustained for 5 overlapping 3-month periods formally designates El Niño.
- The Walker Circulation weakening reduces low-level convergence over the Indian Ocean, suppressing the monsoon trough and delaying or weakening monsoon onset.
- Historically strong El Niño years linked to deficient Indian monsoons: 1972, 1987, 2002, 2009, 2014–15.
- After the 2020–2023 triple-dip La Niña — the first of the 21st century — ENSO dynamics typically swing sharply toward El Niño, which makes the 2026 transition particularly potent.
Connection to this news: IMD's 92% probability of El Niño during the 2026 SWM season is the direct mechanistic driver of the 90% LPA forecast and the potential 11-year-low rainfall scenario.
Heatwave — Definition, Classification, and Governance
A heatwave is a period of abnormally high temperatures that departs significantly from the climatological maximum for a region. The IMD defines a heatwave for plains as a condition where the maximum temperature reaches at least 40°C AND departs from normal by at least 4.5°C; a severe heatwave requires a departure of 6.4°C or more.
- Plains threshold: maximum temperature ≥ 40°C; hilly regions: ≥ 30°C.
- IMD issues colour-coded heat alerts: Green (no action needed), Yellow (watch), Orange (alert/prepare), Red (warning/act).
- The National Disaster Management Authority (NDMA), chaired by the Prime Minister, has issued guidelines for Heat Action Plans at the state level under the Disaster Management Act, 2005.
- Heatwaves are currently not included in the notified list of natural disasters eligible for NDRF (National Disaster Response Fund) relief — a governance gap flagged repeatedly by experts.
- IMD and NDMA are working with 23 states to develop state-specific Heat Action Plans covering heat profiling, historical data, vulnerability mapping, and response protocols.
Connection to this news: With 11 states projected to face heatwave advisories from June 2026 — coinciding with below-normal monsoon onset — the institutional response gap around heatwaves as a recognised disaster category becomes especially relevant.
IMD — Mandate, Forecasting Methods, and Seasonal Outlook Process
The India Meteorological Department (IMD), established in 1875 and functioning under the Ministry of Earth Sciences, is the national authority for weather observation, forecasting, and climate services. Its seasonal monsoon forecast is issued in two stages — a preliminary April forecast and a revised May forecast.
- Forecasting tools: statistical models (based on 8 predictors), dynamical ensemble models (global climate models), and multi-model ensemble (MME) from international centres.
- The LPA (currently 1971–2020 reference period) equals approximately 868.6 mm all-India seasonal rainfall.
- IMD operates more than 2,400 surface observation stations and 3,500 rain-gauge stations.
- In addition to seasonal totals, IMD issues monthly and weekly probabilistic outlooks and district-level heat alerts.
Connection to this news: The revised May forecast reducing the monsoon projection to 90% of LPA — combined with El Niño probability assessment — exemplifies IMD's two-stage operational forecast cycle and its integration of ocean-atmosphere indices.
Key Facts & Data
- 2026 IMD revised monsoon forecast: 90% of LPA (potential 11-year low)
- Probability of El Niño development during June–September 2026: 92%
- States facing heatwave advisories from June 2026: 11
- Northeast India: only major region forecast for normal rainfall
- Central, South Peninsular, and Northwest India: below-normal rainfall expected
- LPA reference period: 1971–2020; all-India average ≈ 868.6 mm
- Deficient monsoon threshold: below 90% of LPA
- IMD established: 1875; functions under Ministry of Earth Sciences
- Heatwave threshold (plains): ≥ 40°C maximum temperature with ≥ 4.5°C departure from normal