NOAA Climate Prediction Center warns of record strong El Nino for fall and winter 2026-27

El Niño is a natural climate pattern that occurs when weakening trade winds allow warmer ocean waters to build up in the central and eastern equatorial Pacific. This shift typically leads to higher global temperatures and altered weather patterns, bringing drought to some regions and heavy rainfall to others. In 2026, ocean temperatures in the tropical Pacific have been climbing rapidly, and on September 10 the NOAA Climate Prediction Center (CPC), part of the National Centers for Environmental Prediction (NCEP) and the National Weather Service (NWS), issued its monthly ENSO Diagnostic Discussion, raising an El Niño Advisory. The advisory states that El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27.

The CPC also gives a 75% chance that the October-December 2026 season will be a historic event that exceeds the strength of all previous El Niño events dating back to 1950. That threshold is defined as a three-month relative Oceanic Niño Index (RONI) value of +2.5°C or more. The ocean is already showing anomalies above +3.0°C in the eastern equatorial Pacific. Except for the Niño-4 index, which decreased to +0.1°C in August, values in the other Niño regions increased, reaching +1.8°C in Niño-3.4, +2.5°C in Niño-3, and +3.4°C in Niño-1+2. Subsurface temperatures showed widespread anomalies in excess of +10.0°C at depth, and low-level westerly wind anomalies reinforced the ocean-atmosphere coupling that drives El Niño.

The CPC outlook indicates that El Niño will continue to strengthen through the end of the year, and the next ENSO Diagnostics Discussion is scheduled for October 8, 2026. NOAA Coral Reef Watch mirrored the advisory on the same day, updating its ENSO Conditions and Coral Bleaching page with the same alert status and forecast numbers. The World Meteorological Organization (WMO), in its Global Seasonal Climate Update for September-October-November 2026 published on September 3, also reported a further development toward stronger El Niño conditions.

Key Facts

The NOAA Climate Prediction Center reported on September 10 that El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27. The center also reported a 75% chance that the October-December 2026 season will be a historic event exceeding the strength of all previous El Niño events since 1950. The official ENSO outlook indicates continued strengthening through the end of the year, and the next discussion is set for October 8, 2026.

Reuters reported on September 10 that the U.S. Climate Prediction Center issued the El Niño Advisory, quoting the center's statement that during the October-December 2026 season there is a 75% chance of a historic event that would exceed the strength of previous El Niño events dating back to 1950. Reuters explained that El Niño occurs naturally when weakening trade winds cause warmer ocean waters to build up in the central and eastern equatorial Pacific, typically leading to higher global temperatures and altered weather patterns, with drought in some regions and heavy rainfall in others. The report included a warning from Jason Nicholls, lead international forecaster at AccuWeather, who said, 'The current El Nino is strong and will continue to strengthen over the coming months and has to be the strongest El Nino on record.' It also noted that Oxfam said El Niño-driven drought has devastated corn and bean crops across Central America's Dry Corridor, pushing tens of thousands of rural households deeper into food and water insecurity, and that the UN Food and Agriculture Organization said El Niño concerns added to weather-driven supply fears in global food markets, contributing to a rise in prices for staples including sugar and vegetable oils.

The World Meteorological Organization reported on September 3 that its Global Seasonal Climate Update for September-October-November 2026 forecasts a further development toward stronger El Niño conditions. Multi-model ensemble forecasts indicate that the seasonal average Niño 3.4 sea surface temperature ensemble mean anomaly is expected to reach approximately 3.6°C during September-November 2026, with the intensification trajectory peaking in November-December. The spread among individual forecast systems generally remains narrow, reflecting high forecast confidence. WMO also expects a positive Indian Ocean Dipole phase to develop, reaching a September-November 2026 seasonal mean value of 0.9°C, while the equatorial Atlantic basin is forecast to remain generally warm.

NOAA Coral Reef Watch reported on September 10 that its ENSO Conditions and Coral Bleaching page, updated with the CPC ENSO Forecast, lists an El Niño Advisory and mirrors the greater than 90% chance of a very strong event. The page reproduces the ocean-temperature indices, the subsurface anomalies above +10.0°C, and the 75% chance of a historic October-December 2026 event. It also notes that El Niño and La Niña events tend to develop during April-June, reach maximum strength during October-February, typically persist for 9 to 12 months, and recur every two to seven years, and that forecast skill is lower during the February-May spring predictability barrier. The update is scheduled for the second Thursday of each month.

Analysis

What this really means is that the world is facing an El Niño event that, if the forecasts hold, will be without precedent in the modern observational record. The CPC's 75% probability of a historic October-December 2026 season is not a routine forecast. It is a statement that the three-month RONI could reach or exceed +2.5°C, a level that would surpass every El Niño event since 1950. The ocean is already showing anomalies above +3.0°C in the eastern equatorial Pacific, and the subsurface has stored widespread anomalies in excess of +10.0°C. Those are not marginal departures from normal; they represent a massive redistribution of heat in the tropical Pacific that will influence weather patterns across the globe.

The bigger picture here is that the convergence of a very strong El Niño with a positive Indian Ocean Dipole and a warm tropical Atlantic creates a compound climate signal. WMO's forecast of a Niño 3.4 anomaly near 3.6°C for September-November 2026, with a peak in November-December, aligns with the CPC's outlook. The narrow spread among forecast systems increases confidence, but it does not eliminate uncertainty. The spring predictability barrier is behind us for this event, and the models have been consistent. Still, the eventual peak will depend on ocean-atmosphere feedbacks that can shift in coming weeks. The fact that the CPC has already raised a 75% chance for a record October-December suggests that the current trajectory is unusually robust.

The judgement from this analysis is that this event should be treated as a high-impact climate emergency in slow motion. It is not simply a warmer-than-average season. The combination of record ocean heat and an expected peak in late 2026 means that drought, flooding, and heat stress will likely hit vulnerable regions hardest. Central America's Dry Corridor is already suffering, according to Oxfam, and global food markets are reacting, according to the FAO. The AccuWeather forecaster's comment that this 'has to be the strongest El Nino on record' is a stark assessment from a private forecasting firm. When a government agency, a UN body, and a private forecaster all point in the same direction, the signals deserve serious attention.

Why It Matters

The impacts of a record El Niño extend far beyond the tropical Pacific. Higher global temperatures are expected, and altered rainfall patterns will bring drought to some regions and heavy rainfall to others. For millions of people who depend on rain-fed agriculture, the difference between a normal season and a strong El Niño can mean the difference between subsistence and hunger. Oxfam's warning that tens of thousands of rural households in Central America's Dry Corridor are already deeper into food and water insecurity shows that the effects are not hypothetical. The FAO's observation that El Niño concerns are contributing to rising prices for sugar and vegetable oils shows that the economic ripples are already spreading through global markets.

The event also matters for ocean health. NOAA Coral Reef Watch is monitoring the situation closely, and while the September 10 update does not issue a specific coral bleaching alert, the presence of sea surface temperature anomalies above +3.0°C in the eastern equatorial Pacific is a significant concern for marine ecosystems. El Niño events can trigger widespread coral bleaching, and the current trajectory suggests that coral reefs in the eastern Pacific and beyond could face severe stress in the coming months. From a global perspective, WMO's key messages include above-normal temperatures worldwide and a classic El Niño footprint in rainfall patterns, with wetter conditions in some regions and increased drought risk in others. The WMO community is mobilising to save lives and livelihoods, but the scale of potential impacts will test early warning systems and humanitarian responses.

Next Up

The next ENSO Diagnostics Discussion from NOAA's Climate Prediction Center is scheduled for October 8, 2026. That update will provide a fresh assessment of whether the strong El Niño is continuing to intensify as forecast, and whether the probability of a historic October-December event remains at 75%. NOAA Coral Reef Watch also plans to update its ENSO Conditions page on the second Thursday of each month, and the World Meteorological Organization is expected to continue issuing seasonal climate updates as the event evolves. Forecasters will be watching the Niño indices, subsurface temperatures, and wind patterns for signs of further strengthening or any unexpected weakening. If the current forecasts hold, the fall and winter of 2026-27 will be remembered as the period when the strongest El Niño since 1950, and possibly on record, reshaped weather patterns, food markets, and climate policy discussions around the world. The coming weeks will determine whether the early warnings were enough to blunt the worst impacts.