WMO El Niño 2026 Data Tracker
Last verified: 9 October 2026 UTC. This tracker separates measurements already observed from seasonal forecasts. It uses figures published by the World Meteorological Organization (WMO); Herald Express does not blend them into a new forecast.
Observed and forecast indicators
| WMO publication date | Indicator | WMO value | Status |
|---|---|---|---|
| 2 June 2026 | Chance of El Niño during June–August | 80% | Forecast issued in June |
| 3 July 2026 | Observed March–May Niño 3.4 seasonal mean | +0.5°C | Observation |
| 3 September 2026 | Observed May–July Niño 3.4 seasonal mean | +1.5°C | Observation |
| 3 September 2026 | Observed July Niño 3.4 monthly mean | +2.0°C | Observation |
| 8 October 2026 | Observed August Niño 3.4 monthly mean | +2.5°C | Observation |
| 8 October 2026 | Forecast October–December Niño 3.4 seasonal mean | Approximately +3.7°C | Forecast, not an observation |
| 8 October 2026 | Forecast October–December Indian Ocean Dipole seasonal anomaly | About +0.5°C | Forecast, not an observation |
Temperature anomalies are in degrees Celsius relative to the WMO product’s 1993–2009 baseline. Values describe ocean or seasonal indicators, not the temperature expected at an individual location.
What changed across the 2026 updates
- Early March: WMO still expected ENSO-neutral conditions to dominate the near term, while noting that El Niño chances rose at longer lead times.
- June: unusually warm tropical Pacific water shifted the outlook, and WMO put the June–August El Niño probability at 80%.
- July and September: the observed Niño 3.4 index strengthened, while multi-model guidance showed a strong to very strong event.
- October: WMO reported a June-to-August increase from +1.6°C to +2.5°C and forecast an October–December seasonal mean near +3.7°C.
What the India signal does and does not mean
WMO’s October seasonal update shows a drier-than-normal signal over the Indian subcontinent for October–December 2026 and a positive Indian Ocean Dipole expected to peak in October. These large-scale probabilities can shift the odds of seasonal rainfall, but they do not determine rainfall in every state, district or week. Decisions about farming, reservoirs, travel or safety should use the latest India Meteorological Department and local-authority forecasts and warnings.
Methodology and update responsibility
- Source selection: only dated WMO El Niño/La Niña Updates, Global Seasonal Climate Updates and related WMO releases are used for the figures above.
- Observed versus forecast: each value is labelled; probabilities and predicted anomalies are not presented as measured outcomes.
- No derived ranking: Herald Express has not recalculated model ensembles or declared a local impact from a global indicator.
- Update responsibility: Herald Express should review this table after each monthly WMO Global Seasonal Climate Update and quarterly El Niño/La Niña Update, recording the new source date and retaining prior observations for chronology.
Related Herald Express coverage
- WMO chief says El Niño could be strongest in four decades
- What a very strong El Niño can mean for weather
- Why El Niño can mean less rain but heavier downpours for India
- Weather, Water & Drought topic hub
Official sources
- WMO, 8 October 2026: Sea-surface temperatures reflect strengthening El Niño
- WMO, 3 September 2026: El Niño set to become very strong
- WMO, 3 July 2026: Global Seasonal Climate Update
- WMO, 2 June 2026: Prepare for El Niño
- WMO El Niño/La Niña Update archive
Corrections
If you believe this resource contains an error, contact Herald Express with the source URL and supporting evidence.