# ECMWF’s El Niño Forecast Moves Its Peak to January as Climate Risks Extend Into 2027

> MKNIRALO — Environment — Climate · El Niño

- Published: 2026-11-07
- Estimated reading time: 6 minutes
- Byline: Mara — Pacific Island Resource and Ocean Policy Observer
- Byline disclosure: Mara is a publication-owned MKNIRALO house editorial byline, not a claim of an independently verified individual. It does not imply Pacific nationality, fisheries licensing, laboratory credentials, village visits, original interviews or direct participation in regional negotiations. Articles distinguish reported findings, proposed measures and verified implementation.
- Author profile: https://mkniralo.com/authors/mara/
- Tags: el-nino, enso, global-heat, climate-forecast, water-security, southeast-asia, pacific-islands, rainfall-risk
- Cover image: https://mkniralo.com/images/el-nino-peak-delayed-january-2027-2026.svg

ECMWF’s latest seasonal run moves the projected Niño 3.4 peak from December to January, while Copernicus gives 2026 a 20% chance of tying or surpassing 2024’s heat record. WMO warns that El Niño-related warmth and rainfall deficits could intensify pressure on Southeast Asian health, farms, water supplies and fire prevention.

The latest ECMWF seasonal forecast places the strongest monthly Niño 3.4 sea-surface-temperature anomaly in January 2027, one month later than its October run. The November forecast puts December at +4.047°C and January at +4.076°C: a difference of just 0.029°C. That is a small model shift, not a sudden change in the ocean. The wider concern is that a very strong El Niño is developing on top of an already exceptionally warm global climate, with rainfall risks extending into 2027.

## A one-month shift, not a new certainty

The November 2026 ECMWF SEAS5 ensemble mean forecasts a Niño 3.4 anomaly of about +4.1°C in January 2027. Its previous monthly run, initialised in October, had December slightly higher than January and therefore placed the peak in December. In the newer run, January edges December by only 0.029°C. The figures are model anomalies against SEAS5’s own 1993–2016 hindcast climate, not absolute ocean temperatures or a measurement of global warming.

That distinction matters because a forecast peak is not a date on which the whole Pacific suddenly changes state. ECMWF’s seasonal system uses a 51-member ensemble and provides a broad outlook over months, with uncertainty around the central estimate. Copernicus’s observed October Niño 3.4 anomaly was +3.21°C using ERA5 and a 1991–2020 reference; it is not directly comparable with the SEAS5 forecast, which uses its own 1993–2016 hindcast climate. WMO’s multi-model outlook gives a different but compatible statistic: an NDJ seasonal mean near +3.8°C, with the warming trend peaking around December.

Sources:
- [Seasonal forecast monthly statistics on single levels](https://www.ecmwf.int/en/forecasts/datasets/seasonal-forecast-monthly-statistics-single-levels) — European Centre for Medium-Range Weather Forecasts (ECMWF)
- [Measuring the strength of El Niño – introducing Relative Niño indices](https://www.ecmwf.int/en/about/media-centre/science-blog/2026/measuring-strength-el-nino) — European Centre for Medium-Range Weather Forecasts (ECMWF)
- [The SEAS5 Explorer](https://forecastseason.com/seas5/) — Forecast Season
- [evolution.json](https://forecastseason.com/assets/seas5/evolution.json) — Forecast Season (ECMWF SEAS5 via Open-Meteo)
- [Copernicus: Warmest October on record with 2026 virtually certain to exceed 1.5°C](https://climate.copernicus.eu/copernicus-warmest-october-record-2026-virtually-certain-exceed-15degc) — Copernicus Climate Change Service
- [Global Seasonal Climate Update for November-December-January 2026](https://wmo.int/resources/publication-series/global-seasonal-climate-updates/gscu-ndj2026) — World Meteorological Organization
- [Seasonal forecasts](https://climate.copernicus.eu/seasonal-forecasts?embed=true) — Copernicus Climate Change Service

## Why the Pacific signal matters

El Niño is the warm phase of the El Niño–Southern Oscillation, a recurring pattern involving the tropical Pacific Ocean and the atmosphere above it. In the Niño 3.4 region, forecasters track sea-surface temperatures across a defined band of the equatorial Pacific. The ocean signal matters because changes in tropical convection and atmospheric circulation can reorganise rainfall and temperature patterns far beyond the Pacific. ECMWF notes that seasonal forecasts use these slower-moving climate patterns to estimate the likelihood of warmer, cooler, wetter or drier conditions over coming months.

The latest ECMWF forecast data show the central Niño 3.4 anomaly continuing to rise from November into January before easing. The month-to-month shift is consistent with the idea that the event is still being fuelled by ocean–atmosphere dynamics, but it should not be reduced to one wind episode or one cause. Westerly wind anomalies and warm-water movement are part of the coupled system; they do not make every regional impact predictable, nor do they remove the uncertainty inherent in a seasonal outlook.

Sources:
- [Seasonal forecast monthly statistics on single levels](https://www.ecmwf.int/en/forecasts/datasets/seasonal-forecast-monthly-statistics-single-levels) — European Centre for Medium-Range Weather Forecasts (ECMWF)
- [Measuring the strength of El Niño – introducing Relative Niño indices](https://www.ecmwf.int/en/about/media-centre/science-blog/2026/measuring-strength-el-nino) — European Centre for Medium-Range Weather Forecasts (ECMWF)
- [The SEAS5 Explorer](https://forecastseason.com/seas5/) — Forecast Season
- [ENSO Diagnostic Discussion](https://cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml) — NOAA Climate Prediction Center
- [Seasonal forecasts](https://climate.copernicus.eu/seasonal-forecasts?embed=true) — Copernicus Climate Change Service

## A hot year before the peak arrives

The El Niño forecast is unfolding against a record-warm background. Copernicus reported that October 2026 was the warmest October in its global record, with an average surface-air temperature of 15.35°C. That was 0.90°C above the 1991–2020 October average and 1.75°C above the estimated 1850–1900 pre-industrial level. Those are different baselines: the first compares October with a recent climate normal; the second compares it with the pre-industrial world.

Copernicus estimates that 2026 is most likely to be the second-warmest calendar year on record, with about an 80% probability, and gives it a 20% chance of matching or exceeding 2024, currently the warmest year. The 20% figure is a probability, not a prediction that a new record will occur. Copernicus also says 2026 is virtually certain to exceed 1.5°C above pre-industrial levels in its annual estimate. El Niño adds a natural source of short-term warming to a climate already warmed by human activities; it is not the sole explanation for the heat.

Sources:
- [Copernicus: Warmest October on record with 2026 virtually certain to exceed 1.5°C](https://climate.copernicus.eu/copernicus-warmest-october-record-2026-virtually-certain-exceed-15degc) — Copernicus Climate Change Service

## Rainfall risks will differ by region

A strong El Niño does not produce the same weather everywhere. WMO’s October seasonal outlook points to warmer conditions and rainfall deficits in Southeast Asia, increasing heat exposure and pressure on agriculture and water supplies, alongside greater wildfire and smoke-haze risks. It also identifies a wetter-than-normal signal in parts of East Africa during the October–December rainy season, with flood concerns, while parts of Southern Africa face increased risk of drier conditions that could affect crops, water availability and livelihoods.

In the western Pacific, WMO’s 5 November outlook points to below-normal rainfall from Palau to the Marshall Islands and from central and southern Papua New Guinea to southern French Polynesia, but wetter-than-usual conditions from Nauru to eastern Kiribati. WMO also reports that Papua New Guinea, Solomon Islands, Vanuatu, Fiji and Tonga experienced water shortages linked to low rainfall between May and October. The outlook is not uniformly dry: even within the Pacific, rainfall signals differ across island groups.

Sources:
- [WMO Global Seasonal Climate Outlook informs humanitarian action](https://wmo.int/media/news/wmo-global-seasonal-climate-outlook-informs-humanitarian-action) — World Meteorological Organization
- [Global Seasonal Climate Update for November-December-January 2026](https://wmo.int/resources/publication-series/global-seasonal-climate-updates/gscu-ndj2026) — World Meteorological Organization
- [ENSO Diagnostic Discussion](https://cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml) — NOAA Climate Prediction Center
- [Western Pacific faces drier months as El Niño strengthens](https://public.wmo.int/media/news/western-pacific-faces-drier-months-el-nino-strengthens) — World Meteorological Organization

## Southeast Asia faces a compound stress test

The WMO warning for Southeast Asia combines three pressures: higher temperatures, less rainfall in some areas and a greater chance of fire and smoke haze. Hot conditions can raise heat exposure, especially where humidity remains high and people work outdoors or lack reliable access to cooling. A rainfall deficit can also reduce the water available to farms and communities. The forecast does not mean every country or watershed will become drier, but it gives governments a reason to check local water, health and agricultural contingency plans before the risk period advances.

The regional health and environmental consequences can reinforce one another. Research from Singapore’s S. Rajaratnam School of International Studies describes how dry conditions can interact with peatland drainage and land-clearing practices, increasing the susceptibility of vegetation and peat to fire. Smoke can then travel across borders, adding air-pollution exposure to heat stress. The analysis cautions against treating El Niño as the only cause: land management, ecosystem condition and local vulnerability shape whether a climate signal becomes a public-health emergency.

Sources:
- [WMO Global Seasonal Climate Outlook informs humanitarian action](https://wmo.int/media/news/wmo-global-seasonal-climate-outlook-informs-humanitarian-action) — World Meteorological Organization
- [El Niño, Heat and Haze: Health Implications for Southeast Asia](https://rsis.edu.sg/rsis-publication/rsis/el-nino-heat-and-haze-health-implications-for-southeast-asia/) — S. Rajaratnam School of International Studies, Nanyang Technological University

## What to watch as 2027 approaches

The forecast should be treated as an early-warning tool, not a substitute for national and local monitoring. WMO says seasonal outlooks are not predictions of individual events and that regional and national forecasts are needed to identify where and when action is required. ECMWF and Copernicus update seasonal guidance as new observations become available. The January peak could move again in a later run, and the small gap between December and January in the current model makes that uncertainty especially important to communicate.

The practical response is less dramatic than the headline but more useful: monitor rainfall, reservoirs and groundwater; prepare farm advisories; protect people exposed to extreme heat; and strengthen fire prevention and smoke-health communication where local forecasts identify elevated risk. For Pacific island water services, the regional outlook is a reason to use island-specific rainfall guidance and local supply monitoring, not to infer household shortages from an ENSO index alone. WMO says the window for preparedness remains open and that forecasts and early-warning systems can help protect lives and livelihoods.

Sources:
- [Seasonal forecast monthly statistics on single levels](https://www.ecmwf.int/en/forecasts/datasets/seasonal-forecast-monthly-statistics-single-levels) — European Centre for Medium-Range Weather Forecasts (ECMWF)
- [WMO Global Seasonal Climate Outlook informs humanitarian action](https://wmo.int/media/news/wmo-global-seasonal-climate-outlook-informs-humanitarian-action) — World Meteorological Organization
- [Western Pacific faces drier months as El Niño strengthens](https://public.wmo.int/media/news/western-pacific-faces-drier-months-el-nino-strengthens) — World Meteorological Organization
- [Seasonal forecasts](https://climate.copernicus.eu/seasonal-forecasts?embed=true) — Copernicus Climate Change Service

## About this article

This article reflects the public sources available on the publication and update dates shown above. For developing stories, follow the linked source pages for subsequent statements or decisions.

## Sources and further reading

- [Seasonal forecast monthly statistics on single levels](https://www.ecmwf.int/en/forecasts/datasets/seasonal-forecast-monthly-statistics-single-levels) — European Centre for Medium-Range Weather Forecasts (ECMWF) (accessed 2026-11-07)
- [Measuring the strength of El Niño – introducing Relative Niño indices](https://www.ecmwf.int/en/about/media-centre/science-blog/2026/measuring-strength-el-nino) — European Centre for Medium-Range Weather Forecasts (ECMWF) (published 2026-06-10) (accessed 2026-11-07)
- [The SEAS5 Explorer](https://forecastseason.com/seas5/) — Forecast Season (accessed 2026-11-07)
- [evolution.json](https://forecastseason.com/assets/seas5/evolution.json) — Forecast Season (ECMWF SEAS5 via Open-Meteo) (published 2026-11-05) (accessed 2026-11-07)
- [Copernicus: Warmest October on record with 2026 virtually certain to exceed 1.5°C](https://climate.copernicus.eu/copernicus-warmest-october-record-2026-virtually-certain-exceed-15degc) — Copernicus Climate Change Service (published 2026-11-05) (accessed 2026-11-07)
- [WMO Global Seasonal Climate Outlook informs humanitarian action](https://wmo.int/media/news/wmo-global-seasonal-climate-outlook-informs-humanitarian-action) — World Meteorological Organization (published 2026-10-26) (accessed 2026-11-07)
- [Global Seasonal Climate Update for November-December-January 2026](https://wmo.int/resources/publication-series/global-seasonal-climate-updates/gscu-ndj2026) — World Meteorological Organization (published 2026-10-21) (accessed 2026-11-07)
- [ENSO Diagnostic Discussion](https://cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml) — NOAA Climate Prediction Center (published 2026-10-08) (accessed 2026-11-07)
- [El Niño, Heat and Haze: Health Implications for Southeast Asia](https://rsis.edu.sg/rsis-publication/rsis/el-nino-heat-and-haze-health-implications-for-southeast-asia/) — S. Rajaratnam School of International Studies, Nanyang Technological University (published 2026-09-09) (accessed 2026-11-07)
- [Western Pacific faces drier months as El Niño strengthens](https://public.wmo.int/media/news/western-pacific-faces-drier-months-el-nino-strengthens) — World Meteorological Organization (published 2026-11-05) (accessed 2026-11-07)
- [Seasonal forecasts](https://climate.copernicus.eu/seasonal-forecasts?embed=true) — Copernicus Climate Change Service (published 2026-10-10) (accessed 2026-11-07)