El Nino strengthened rapidly, firmly established, may intensify further: WMO
The World Meteorological Organization (WMO) has confirmed that El Nino conditions in the equatorial Pacific have strengthened rapidly and are now firmly established
The Nino 3.4 sea surface temperature anomaly index rose from about +1.5 degrees Celsius above normal in mid-2026 to over +2 degrees Celsius by July, with readings of 2.2-2.6 degrees Celsius above average recorded by mid-August
WMO has stated a near-100% probability of the El Nino event persisting through February 2027, with peak intensity expected around the end of 2026
Regional rainfall shifts are forecast, including drier conditions across South Asia, Southeast Asia, Australia and Central America, and wetter conditions in the Horn of Africa and parts of South America
El Nino-Southern Oscillation (ENSO) — Definition and Monitoring
El Nino is the warm phase of the El Nino-Southern Oscillation (ENSO), a naturally occurring cycle of alternating warm (El Nino) and cool (La Nina) sea surface temperature anomalies in the central and eastern equatorial Pacific Ocean, coupled with corresponding shifts in atmospheric pressure (the Southern Oscillation) between the eastern and western Pacific. ENSO is the single largest driver of year-to-year variability in global weather patterns.
WMO's confirmation that the event is "firmly established," based on Nino 3.4 anomalies already well above the +0.5 degrees Celsius threshold and still rising, reflects the standard technical basis on which El Nino episodes are formally declared and tracked.
El Nino's Effect on the Indian Summer Monsoon
El Nino years are statistically associated with a weaker and more erratic Indian summer monsoon (ISMR), because warmer central-eastern Pacific waters shift the Walker Circulation and typically suppress the low-pressure systems that drive monsoon rainfall over the Indian subcontinent. However, the correlation is probabilistic, not deterministic — outcomes also depend on the Indian Ocean Dipole (IOD) and other factors.
Key Details
- Of roughly 16 El Nino events recorded in India since 1950, about 7 have been associated with significant all-India monsoon deficiency; several severe historical droughts (including the Great Famine period of 1876-78) coincided with strong El Nino years
- The El Nino-monsoon correlation has weakened somewhat since the 1980s, attributed to changes in ocean-atmosphere coupling; a positive Indian Ocean Dipole can partly offset El Nino's drying effect on the monsoon, as seen in some recent El Nino years that still recorded near-normal rainfall
- The India Meteorological Department (IMD) issues its Long Range Forecast for the monsoon incorporating ENSO status, IOD phase, and other predictors, typically in April and again with an update in late May/June
- El Nino years also tend to correlate with warmer winters and a higher probability of heatwave conditions over parts of India
With WMO assessing a near-certain probability of the event persisting through February 2027 and forecasting drier conditions over South Asia, this El Nino episode carries direct relevance for India's monsoon outlook, water availability, and agricultural planning in the affected crop seasons.
Institutional Framework — WMO and Global Climate Services
The World Meteorological Organization is the United Nations' specialized agency for weather, climate and water, responsible for coordinating global meteorological observation, standardising forecasting methodology, and issuing authoritative international assessments such as El Nino/La Nina updates.
WMO's statement of "near-100% probability" reflects the culmination of coordinated global observation and modelling by its member meteorological services, underscoring why WMO assessments (rather than any single national forecast) are treated as the authoritative reference point for El Nino status.
- Nino 3.4 index: approximately +1.5 degrees Celsius (mid-2026) rising to +2.2 to +2.6 degrees Celsius above average by mid-August 2026
- WMO-assessed probability of El Nino persisting through February 2027: near 100%
- Peak intensity expected: around end of 2026
- Standard NOAA El Nino declaration threshold: ONI at or above +0.5 degrees Celsius for 5+ consecutive overlapping 3-month periods
- Nino 3.4 monitoring region: 5°N-5°S, 170°W-120°W in the equatorial Pacific
- El Nino events since 1950 associated with major Indian monsoon deficiency: approximately 7 of 16
- WMO established: 1950; headquartered in Geneva; 193 members