El Niño 2026: How Strong It Is and What It Means for Winter

Is El Niño happening in 2026?

Yes. El Niño is under way and still strengthening: NOAA's Climate Prediction Center (CPC) kept its official El Niño Advisory in place on 12 November 2026 ^[1]. An advisory is issued when El Niño conditions are observed and expected to continue ^[9].

The CPC reported that sea surface temperature anomalies exceeded 4.0°C in parts of the eastern equatorial Pacific and that the main index, Niño-3.4, rose to +2.5°C, with +3.6°C in Niño-3 and +4.4°C in Niño-1+2 near South America ^[1]. Below the surface, temperatures at depth in the eastern Pacific were more than 10.0°C above average ^[1]. The atmosphere is responding in the classic El Niño way: rainfall is enhanced from the central to the eastern Pacific and suppressed over Indonesia ^[1].

The event grew quickly. WMO says the Niño-3.4 region still showed weak La Niña conditions at the start of 2026, then its temperature anomaly rose by more than 1.5°C between March and August; El Niño conditions emerged in June and were firmly established by mid-August ^[6].

How strong will El Niño 2026 get?

Forecasters expect a strong to very strong event, possibly the strongest since records in this series began in 1950 ^[1][4]. NOAA gives a better than 79% chance of a strong-to-very-strong El Niño lasting through January-March 2027, and about a 60% chance of a historic event, meaning a 3-month RONI (Relative Oceanic Niño Index) of +2.5°C or more that would beat any El Niño since 1950, for the October-December and November-January periods ^[1].

WMO's Global Seasonal Climate Update, issued on 21 October 2026, forecasts the Niño-3.4 anomaly to reach about +3.8°C on average over November 2026 to January 2027, with warming peaking around December 2026, and says the spread between forecast systems is narrow ^[3]. In a statement for a COP31 event, published on 10 November, WMO Secretary-General Celeste Saulo said that 13 forecasting centres now agree and that the Pacific could reach 3.8 degrees above normal by the end of the year, which "would make this the strongest El Nino since at least 1950" ^[4].

A note on numbers: a "very strong" El Niño is generally defined by a three-month average anomaly of at least 2.0°C in the Niño-3.4 region ^[6]. NOAA's historic-event odds are given in a newer relative index (RONI) that measures warming relative to the global ocean, so they should not be read directly against the traditional Niño-3.4 values quoted above ^[1][2][8].

When will El Niño peak and end?

The peak is expected around December 2026, followed by gradual weakening in early 2027 ^[1][3]. NOAA's model summary says El Niño will continue to strengthen before beginning to weaken in early 2027 ^[1].

WMO said on 3 September that the chance of El Niño lasting through February 2027 was "nearly 100%", the first time a WMO update had been so unequivocal ^[2]. A WMO regional note on 5 November said the event is expected to persist into the March-May 2027 period, and that some countries are likely to feel its effects after it ends ^[5].

That lag matters. WMO notes that El Niño's effect on global temperatures can be most pronounced in the year after it develops ^[2]. NOAA's next ENSO diagnostic discussion is due on 10 December 2026 ^[1].

What does El Niño mean for winter weather?

It shifts the odds, not the certainty: NOAA's US Winter Outlook for December 2026 to February 2027, issued on 15 October 2026, favours warmer-than-average temperatures across the northern US and wetter-than-average conditions across the southern US and East Coast ^[7].

• Warmer than average: favoured for northern California, the Pacific Northwest, the Midwest, the Mississippi Valley, much of the East, Alaska, and Puerto Rico and the US Virgin Islands ^[7].
• Near normal temperatures: most likely for parts of the Southeast, including Florida ^[7].
• Wetter than average: most likely across the southern tier from the Southwest to the Southeast, and along the East Coast ^[7].
• Drier than average: elevated odds for Hawaii, much of Alaska, the northern Mountain West and some areas of the Great Lakes ^[7].
• Drought: forecast to improve or end in the Southwest, Southern Great Plains, Southeast and parts of the East Coast ^[7].

NOAA's National Weather Service director Ken Graham warned that while more rain and snow may ease drought, "too much precipitation on dry soil can fuel destructive flash floods and mudslides" ^[7]. NOAA updates its three-month outlook monthly; the next update is due on 19 November ^[7].

What are the effects of El Niño around the world?

WMO's multi-model forecasts point to above-normal temperatures over almost all land areas, but the effects differ sharply by region ^[2][8]. These are probabilities from seasonal forecasts, not predictions of specific events.

• Western and south-west Pacific: WMO expects drier weather from November 2026 to January 2027 from Palau to the Marshall Islands and from central and southern Papua New Guinea to southern French Polynesia; Papua New Guinea, the Solomon Islands, Vanuatu, Fiji and Tonga already reported water shortages linked to low rainfall from May to October ^[5].
• Central Pacific: a wetter season along the equator from Nauru to eastern Kiribati, with strong marine heatwaves and coral bleaching risk around eastern Kiribati ^[5].
• Southern Africa: a humanitarian briefing by Welthungerhilfe (published 10 November, drawing on WMO, NOAA and other forecasts) calls it the clearest emerging agricultural drought concern, with roughly 50-80% chances of below-normal rain across much of the region from November 2026 to March 2027 ^[8].
• Central America and northern South America: the same briefing reports a broad dry and hot signal ^[8].
• East Africa and parts of Asia: the same briefing, summarising the WMO Coordination Mechanism seasonal outlook for November 2026 to January 2027, reports wetter conditions in parts of East Africa and central and eastern Asia ^[8].

For local detail, WMO says national weather services remain the authoritative source of warnings ^[2].

What is El Niño, and is it caused by climate change?

El Niño is the warm phase of the El Niño-Southern Oscillation (ENSO), a natural climate pattern characterised by a warming of ocean surface temperatures in the central and eastern equatorial Pacific ^[2]. Its opposite phase is La Niña ^[2].

WMO says El Niño typically occurs every two to seven years, lasts about nine to twelve months, usually begins developing between March and June and peaks between November and February ^[2]. WMO says El Niño can reshape weather and climate patterns thousands of kilometres away from the tropical Pacific ^[2]. NOAA describes the US effect as a southward and eastward shift in the jet stream that tilts the odds toward stormier weather across the South ^[7].

WMO states plainly that El Niño "is a natural climate phenomenon and is not caused by climate change" ^[2]. WMO's Secretary-General also says that what each event does depends more and more on how human activities are affecting the climate ^[4]. The State of the Climate 2026: What WMO's COP31 Report Says guide covers that background warming.

How should you prepare for El Niño?

Use your national weather service's seasonal outlook and warnings, not viral maps or single-model forecasts ^[2][7]. Seasonal outlooks give probabilities for a three-month period; they cannot say whether a storm will hit a given town on a given day.

• Check the official local outlook monthly. In the US that is NOAA's seasonal outlook, updated monthly; elsewhere, the national meteorological service ^[2][7].
• Plan for both extremes where relevant. NOAA notes that the same winter can bring drought relief and flash floods on dry ground ^[7].
• Watch water and heat risks. WMO highlights water shortages in Pacific islands and higher temperatures that can worsen drought where El Niño brings less rain ^[5].
• Remember that impacts outlast the peak. WMO says effects will last well into 2027 ^[4].

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What is still uncertain?

The overall pattern is high-confidence; the local details are not ^[3][4]. WMO's Saulo said that what the event will do "in each country is far harder to predict" than its strength ^[4].

• Exact peak value: WMO's forecast ensemble gives about +3.8°C in Niño-3.4 for November-January ^[3], while NOAA puts the chance of a 3-month RONI of +2.5°C or more at about 60% ^[1]. These use different indices.
• Other ocean drivers: a positive Indian Ocean Dipole developed this autumn and is forecast to fade toward normal over November-January; a warm tropical Atlantic can also reinforce, weaken or alter typical El Niño effects ^[2][3].
• Regional surprises: WMO notes that "no two El Niño events are the same" ^[4].

NOAA itself cautions that even with a very strong El Niño, impacts consistent with El Niño are more likely but "not guaranteed" ^[1].