WMO seasonal update forecasts a further strengthening of El Nino into December
8 October 2026
The World Meteorological Organization published its Global Seasonal Climate Update for October to December 2026.
The update says forecasts point to a further intensification towards stronger El Nino conditions.
The Nino 3.4 sea-surface temperature anomaly is forecast at about plus 3.7 degrees Celsius for the season, peaking around December 2026.
Forecast systems agree closely with one another, which the update treats as high confidence.
Most regions are expected to be warmer than normal, especially in the Northern Hemisphere and across equatorial regions.
A positive Indian Ocean Dipole is expected to peak in October and then weaken, leaving a seasonal mean anomaly of plus 0.5 degrees Celsius.
The equatorial Atlantic is expected to stay warm, with both the North and South Tropical Atlantic above normal.
In plain words
Nino 3.4 Nino 3.4 region — A box in the central equatorial Pacific whose sea-surface temperature anomaly is the standard measure of El Nino strength.
IOD Indian Ocean Dipole — The difference in sea-surface temperature between the western and eastern tropical Indian Ocean.