WMO forecasts El Niño strengthening toward December peak, with record Pacific anomaly

The World Meteorological Organization said on October 8 that El Niño is forecast to strengthen toward a peak around December 2026, raising the risk of unusually high temperatures and shifts in rainfall across much of the world. Its October-to-December outlook projects a record seasonal sea-surface temperature anomaly in the central and eastern equatorial Pacific. Those figures are forecasts, while a separate US model points to an earlier peak.

How strong does WMO expect El Niño to become?

WMO forecasts the seasonal average Niño 3.4 anomaly, a measure of sea-surface temperature in a central and eastern equatorial Pacific region, to reach about 3.7°C above its reference level from October through December. The agency describes that figure as higher than any recorded since observations began. It says the previous record was 2.6°C, set during November 2015 through January 2016. The projected 3.7°C is therefore a possible record, not an observed one.

The agency says the anomaly rose from an average 1.6°C in June to 2.5°C in August. Its seasonal update draws on a consensus across 13 national and international meteorological centres. WMO Secretary-General Celeste Saulo called El Niño ‘firmly established and strengthening rapidly’ and said WMO forecasts give it a near-100% likelihood of persisting through February 2027. She said it could become one of the strongest events since at least 1950.

El Niño is the warm phase of a recurring pattern in the tropical Pacific that affects winds, pressure and rainfall far beyond the ocean where it develops. WMO expects above-average temperatures across much of the globe and changes in rainfall patterns that increase drought and flood risks in different regions. The outlook describes broad risks; it does not establish which individual places will experience drought, flooding or particular losses.

Why the Pacific forecast matters beyond the Pacific

Saulo said El Niño does not create new heat for the planet: it releases heat already stored in the ocean. She described the ocean feeding this event as the warmest measured. WMO says the resulting temperature effects will compound those of human-caused climate change. That distinction matters when reading the forecast: an El Niño signal can affect a particular season, while the warmer background climate is a separate, continuing influence.

Where the WMO and NOAA forecasts differ

An October 7 experimental forecast from the US National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory says this El Niño is nearing its peak and should weaken by early winter. WMO’s outlook instead forecasts further intensification toward a peak around December. The two assessments use different forecast systems and describe timing differently; neither has yet measured the eventual peak.

The NOAA laboratory’s SPEAR prediction system uses 30 individual model runs. Its October outlook says impacts may continue to intensify in parts of the United States even if El Niño weakens during winter. It projects a move to neutral conditions in spring or early summer, but says the spread among model runs grows during those later months. That widening spread is a reason to treat the projected end of the event with more caution than its nearer-term trajectory.

NOAA GFDL says its current forecast exceeds any El Niño observed in at least the past 30 years, with the 1997–98 extreme event a close second in its comparison. This compares a forecast with past observations; it is not a declaration that the current event has already set that record. Similarly, WMO’s projected 3.7°C seasonal anomaly remains a prediction until the October-to-December period has been observed.

What remains uncertain about local impacts

Both outlooks point to a powerful event, but their different peak timing shows why a seasonal forecast should not be read as a precise timetable for any community. WMO identifies worldwide temperature and rainfall risks, while NOAA GFDL highlights the possibility of intensifying effects in parts of the United States. Neither assessment in these reports confirms a specific future flood, drought or temperature outcome at a particular location. Later observations will determine the event’s actual peak and duration.