This is Breliio's live 2026–27 El Niño tracker.
Unlike our evergreen guide to what El Niño is and how ENSO works, this page is designed to change.
The newest update stays at the top. Older updates remain below it so you can see not only what forecasters believe now, but how the forecast evolved.
We track observed Pacific temperatures, NOAA's official ENSO probabilities and strength outlook, IRI's multi-model plume, WMO seasonal forecasts and credible regional impact outlooks. We also separate observations from model projections so that a forecast number is never presented as though it has already happened.
El Niño is already here—and it is intensifying rapidly.
NOAA's ENSO Alert System remains at El Niño Advisory. The official October assessment describes a strengthening event with a strong-to-very-strong El Niño likely through January–March 2027. The latest IRI observations show an exceptionally high weekly traditional Niño-3.4 anomaly, while WMO's newest global seasonal forecast expects further strengthening toward a December peak.
Latest update: October 22, 2026
WMO lifts its projected November–January Niño-3.4 mean to about +3.8°C
This is the newest major international seasonal update available at publication time.
The number is eye-catching, but it needs context. It is a forecast ensemble mean, not an observed weekly reading and not NOAA's RONI. It therefore should not be used as though it were directly comparable with NOAA's “very strong” historical RONI threshold.
The same WMO update expects the positive Indian Ocean Dipole to weaken toward climatology, with a November–January seasonal mean around +0.3°C, while the equatorial Atlantic remains warmer than normal. Those other ocean basins matter because actual regional weather in 2026–27 will reflect more than ENSO alone.
Tracker assessment: the direction of travel remains clear. The event is not merely persisting; the major observing and forecast systems still support further near-term strengthening before a likely late-2026 peak.
Weekly Niño-3.4 reaches +3.3°C; 27-model plume remains exceptionally bullish
IRI's October Quick Look reports the latest weekly traditional Niño-3.4 value, centered on October 14, at +3.3°C. Weekly anomalies in the central/eastern equatorial Pacific had remained above +3.0°C for five consecutive weeks.
Its historical sequence is striking: the July–September seasonal mean reached +2.46°C; September's monthly value reached +2.84°C; then the mid-October weekly value rose to +3.3°C.
The October prediction plume includes 27 models—16 dynamical and 11 statistical. The combined mean forecasts approximately +3.5°C in both October–December and November–January on the traditional Niño-3.4 metric.
IRI's objective probability system assigns a 100% El Niño probability through March–May 2027, easing to 92% in April–June and 60% in May–July; by June–August 2027, neutral becomes the most likely category at 51%.
Tracker assessment: model disagreement is currently more about how extreme the peak becomes and how quickly it weakens than about whether El Niño persists through winter.
WMO highlights food, fisheries and Pacific marine risks
WMO's World Food Day update says the intensifying El Niño is already a major planning issue for agriculture, fisheries, water management, disaster response and health.
Among the specific developments it highlighted: anchoveta fishing in Peru had been suspended to protect stocks; unusually warm Pacific waters were increasing concern over marine heatwaves and coral bleaching; and the Pacific had experienced high tropical-cyclone activity.
These are important impact signals, but they should not be read as proof that every individual event was “caused by El Niño.” ENSO changes background ocean and atmospheric conditions and therefore changes risk.
NOAA's 2026–27 U.S. Winter Outlook is heavily influenced by the very strong El Niño
NOAA's winter outlook favors warmer-than-average conditions across much of the northern United States and wetter-than-average conditions across much of the southern tier and East Coast.
NOAA specifically links the winter pattern to an expected southward/eastward shift in the jet stream during a very strong El Niño. It also forecasts drought improvement across much of the Southwest, Southern Great Plains, Southeast and East Coast, while warning that heavy precipitation over dry terrain can create flash-flood and mudslide risks.
This is a seasonal probability outlook, not a snowfall forecast. NOAA explicitly notes that seasonal snowfall totals generally cannot be predicted reliably months in advance.
Very strong El Niño incorporated into South Asia's October–December climate outlook
The South Asian Climate Outlook Forum, coordinated with WMO and regional agencies, issued an outlook reflecting the very strong El Niño now present.
It favors normal-to-above-normal rainfall over northwestern and parts of eastern and southern South Asia, while below-normal rainfall is favored across much of central and southern peninsular South Asia and some eastern areas. Normal-to-above-normal temperatures are favored across most of the region.
Tracker assessment: this is a good example of why “El Niño means wetter” is wrong. Even within one region, the forecast contains both wetter and drier zones.
NOAA raises the probability of a historic-strength event
NOAA reported that El Niño had strengthened further during September. Its monthly indices reached approximately +2.1°C in Niño-3.4, +3.0°C in Niño-3 and +3.9°C in Niño-1+2, while parts of the eastern equatorial Pacific exceeded +4.0°C.
The subsurface signal was also extreme: the equatorial thermocline remained deeper than average, with subsurface temperature anomalies above +10°C at depth in parts of the eastern Pacific.
Atmospheric coupling was unmistakable: low-level westerly wind anomalies extended from the western into the east-central Pacific, upper-level easterly anomalies were present, rainfall/convection was enhanced from the central into the eastern Pacific and suppressed over Indonesia, and Southern Oscillation indices were strongly negative.
NOAA's key strength forecast was especially notable. It estimated the chance of reaching or exceeding +2.5°C on the three-month RONI scale at 54% for September–November, 83% for October–December and 70% for November–January.
That is NOAA's definition of a possible event exceeding the RONI strength of any previous El Niño in its post-1950 comparison period—not a guarantee that every regional impact will also be historically extreme.
WMO forecasts around +3.7°C for October–December
WMO's October–December Global Seasonal Climate Update forecast an ensemble-mean Niño-3.4 anomaly of about +3.7°C and projected the warming trend to peak around December.
The very next WMO monthly update, issued October 21, nudged the following November–January seasonal mean to around +3.8°C. That is why this tracker keeps old forecast values visible rather than overwriting them: you can see the forecast evolve.
NOAA GFDL SPEAR suggests the event may be near its maximum—but impacts can strengthen after SSTs peak
NOAA GFDL's experimental SPEAR forecast started October 1 and suggested this historic El Niño was nearing its peak, with weakening expected by early winter and a transition toward neutral conditions during spring or early summer 2027.
This does not necessarily conflict with WMO's forecast for a December seasonal peak. Different models, metrics, initialization dates and averaging periods can place the exact maximum at slightly different times.
More importantly, GFDL stresses that impacts can continue intensifying even after the ocean index begins to weaken. Atmospheric teleconnections have their own seasonal timing, so “El Niño has peaked” does not mean “El Niño's weather impacts are over.”
Regional outlook warns of simultaneous drought, flood, heat and cyclone risks
The South-West Indian Ocean Climate Outlook Forum warned against treating El Niño as one single regional hazard.
Southern parts of the region—including South Africa, southern/central Mozambique, Malawi and southwestern Madagascar—face increased drought and water-stress risks. Northern areas including Tanzania, northern Malawi and parts of the islands face greater flood and landslide risk. Above-normal temperatures are favored across the region.
The forum also expects below-normal tropical cyclone activity for the basin overall, with possible track shifts—but emphasized that reduced basin-wide activity does not eliminate local cyclone danger.
The forecast dashboard
| Source | Latest issue | Metric | Current / forecast signal | What it means |
|---|---|---|---|---|
| NOAA CPC | Oct. 8 | Official RONI + coupled ENSO assessment | Strong-to-very-strong event likely through Jan.–Mar. 2027; 83% chance OND RONI ≥ +2.5°C. | Official U.S. operational ENSO outlook. |
| IRI | Oct. 19 | Traditional Niño-3.4 observations + 27-model plume | Weekly Niño-3.4 +3.3°C centered Oct. 14; model mean ~+3.5°C OND and NDJ. | Shows present SST intensity and broad model agreement. |
| WMO | Oct. 21 | Global multi-model Niño-3.4 seasonal forecast | ~+3.8°C ensemble mean for NDJ 2026–27; peak around Dec. | Newest international seasonal consensus. |
| NOAA GFDL SPEAR | Oct. 7 | Experimental coupled model | Near peak, weakening through winter; neutral favored spring/early summer. | Useful model perspective, not the official NOAA consensus. |
NOAA's official probability path
NOAA's October probability table makes one thing especially clear: the main uncertainty is now about strength and eventual decay, not whether El Niño exists.
| Season | El Niño | Neutral | La Niña |
|---|---|---|---|
| Sep–Nov 2026 | 100% | 0% | 0% |
| Oct–Dec 2026 | 100% | 0% | 0% |
| Nov 2026–Jan 2027 | 100% | 0% | 0% |
| Dec 2026–Feb 2027 | 100% | 0% | 0% |
| Jan–Mar 2027 | 100% | 0% | 0% |
| Feb–Apr 2027 | 98% | 2% | 0% |
| Mar–May 2027 | 85% | 15% | 0% |
| Apr–Jun 2027 | 45% | 54% | 1% |
| May–Jul 2027 | 17% | 70% | 13% |
NOAA's official forecast therefore favors El Niño through boreal spring, with ENSO-neutral becoming the most likely state in April–June 2027.
IRI's model-only probabilities retain El Niño somewhat longer than NOAA's official human-reviewed forecast, illustrating why a good tracker should show more than one model product rather than presenting a single line as certainty.
How fast did this El Niño develop?
The reverse chronology makes the acceleration easier to appreciate.
The most important signal is not one SST number—it is ocean–atmosphere coupling
The 2026 event has passed well beyond “the Pacific is warm.”
NOAA's October diagnostic shows the coupled ENSO system operating in textbook fashion:
Ocean
Extreme surface warming from the central into the eastern Pacific, a deeper eastern thermocline and very large positive subsurface temperature anomalies.
Winds
Low-level westerly anomalies weaken or reverse the normal easterly trades across large parts of the equatorial Pacific.
Rainfall & pressure
Convection has shifted into the central/eastern Pacific, rainfall is suppressed around Indonesia, and Southern Oscillation indices are strongly negative.
This is why the current event deserves more confidence than a forecast based solely on one warm sea-surface-temperature region.
For the mechanics—trade winds, thermocline, Walker circulation, Kelvin waves and Bjerknes feedback—see our full guide to how El Niño works.
What is happening in the real world?
This section tracks credible regional outlooks and observed impacts associated with the developing El Niño background. It deliberately avoids saying El Niño “caused” every storm, drought or flood occurring during the event.
Winter odds tilt wetter south, warmer north
NOAA's October 15 winter outlook favors a wetter southern tier and East Coast, warmer conditions across much of the northern U.S., and drought improvement in several southern/eastern regions.
Mixed rainfall signal
The October South Asia outlook favors normal-to-above-normal rainfall in some northwestern, eastern and southern areas but below-normal rain across much of central and southern peninsular South Asia.
Drought and flood risks at the same time
Regional outlooks raise drought risk in southern areas and flood/landslide risk farther north, with unusually high temperatures favored widely.
Marine heat becomes an economic issue
WMO reported Peru had suspended anchoveta fishing to protect stocks and highlighted risks from marine heatwaves and coral bleaching across the Pacific.
Is this really on track to be “historic”?
Potentially, yes—depending on the metric.
NOAA's October official strength outlook explicitly says there is a high chance that the event will exceed the strength of previous El Niños dating back to 1950 on its three-month RONI metric. The October–December probability of ≥+2.5°C is 83%.
IRI's traditional Niño-3.4 observations are also extraordinarily high, with the weekly value at +3.3°C centered October 14.
WMO's multi-model seasonal forecast is even higher numerically, at around +3.8°C for November–January.
But this is exactly where headlines can go wrong.
For that reason, this tracker will use phrases such as historic-strength by NOAA's RONI metric rather than simply declaring “the strongest El Niño ever” before the seasonal event is complete.
When is it expected to peak?
The consensus is broadly late 2026, but the precise peak depends on metric.
WMO's October 21 update expects warming to peak around December 2026.
IRI's October model mean remains near its maximum across October–December and November–January.
NOAA GFDL's experimental SPEAR model, meanwhile, says the event may already be near its maximum and forecasts weakening through early winter.
Those views are not as contradictory as they appear. A weekly SST peak can occur before a three-month seasonal index peaks, and the atmospheric impacts can peak later still.
When might it end?
NOAA's October official probabilities keep El Niño at essentially 100% through January–March 2027 and 98% through February–April.
By March–May, the official probability falls to 85%.
For April–June, neutral narrowly becomes most likely at 54%, versus 45% El Niño.
By May–July, neutral is strongly favored at 70%.
IRI's objective model plume is slower to let go of El Niño, with 60% El Niño probability still in May–July before neutral takes the lead in June–August.
So the most defensible current statement is:
El Niño is highly likely to dominate through winter 2026–27, remain present into boreal spring, and then weaken toward neutral conditions sometime around late spring or early summer 2027.
What could change the story from here?
The event is now so established that a sudden return to neutral this winter is extremely unlikely. But several questions remain open.
How high is the final peak?
Does Niño-3.4 continue rising into November/December, plateau near current levels, or begin weakening sooner?
Where is the strongest warming?
The longitude of peak SST and convection matters for teleconnections, not just the basin-average number.
How quickly does the subsurface reservoir cool?
Upper-ocean heat content and thermocline changes provide clues about how durable the event will be.
Do westerly wind anomalies persist?
Persistent atmospheric coupling can maintain eastward warm-water anomalies; a reversal can help begin decay.
How do the Indian and Atlantic Oceans evolve?
The weakening positive IOD and warm tropical Atlantic can modify regional rainfall and cyclone outcomes.
How do winter teleconnections verify?
Seasonal forecasts describe probabilities. The next major question is how closely observed winter weather follows the expected El Niño pattern.
What we'll update every week
This tracker is designed around a repeatable checklist so the page does not turn into a stream of disconnected headlines.
| Weekly check | What we look for | Why it matters |
|---|---|---|
| Niño-3.4 | Newest weekly and monthly SST anomaly | Tracks the surface intensity and whether warming is still accelerating. |
| Subsurface heat | Warm-water volume, thermocline depth, eastern-Pacific anomalies | Shows whether the ocean still has fuel beneath the surface. |
| Trade winds | Low-level westerly/easterly anomalies | Tests whether atmosphere–ocean coupling is strengthening or weakening. |
| Convection | Rainfall/cloud anomalies across Indonesia and central/eastern Pacific | Shows whether the atmospheric side of ENSO remains locked in. |
| NOAA probabilities | Official phase and strength probabilities | Best operational consensus rather than one model run. |
| IRI plume | Model ensemble mean and spread | Tracks forecast agreement and timing of expected decay. |
| WMO outlook | Global multi-model update | Provides international consensus and global seasonal context. |
| Regional impacts | Official seasonal outlooks, fisheries, drought, floods, cyclone risks | Connects the climate index to real planning consequences without over-attribution. |
Upcoming dates to watch
Weekly: NOAA CPC updates ENSO current-condition data, including weekly ocean indicators.
November 12, 2026: NOAA's next full monthly ENSO Diagnostic Discussion is scheduled. This is the next major official checkpoint for updated probabilities and strength assessment.
November 19, 2026: NOAA's next U.S. seasonal outlook update is scheduled.
Late November: WMO's next Global Seasonal Climate Update should give another international multi-model look at the expected peak and early-2027 decay.
Every new IRI plume: watch whether the model mean still reaches the mid-+3°C range and whether the projected transition back toward neutral moves earlier or later.
How to interpret scary El Niño headlines
Ask which metric
Weekly Niño-3.4, seasonal Niño-3.4, ONI and RONI are not identical.
Ask observed or forecast
A model projecting +3.8°C is different from an observation of +3.8°C.
Ask which period
A weekly peak can be much higher than a three-month seasonal mean.
Ask which region
Niño-1+2 can be extreme near South America while Niño-4 remains much less anomalous.
Ask probability or certainty
Seasonal rain and temperature maps show shifted odds, not guaranteed weather.
Ask whether attribution is justified
An event occurring during El Niño is not automatically an event caused by El Niño.
The story so far
In May, the Pacific was technically still ENSO-neutral, but the subsurface ocean was warming quickly enough for NOAA to issue an El Niño Watch.
In June, El Niño arrived.
By August and September, it was accelerating toward very strong territory.
By October, the event had become exceptional: a +3.3°C weekly traditional Niño-3.4 reading from IRI, extreme eastern-Pacific and subsurface warmth, an 83% NOAA chance of a historic-strength October–December RONI event, and WMO models projecting a roughly +3.8°C November–January Niño-3.4 seasonal mean.
The central question is no longer whether El Niño 2026–27 happens. It is how extreme the peak becomes, how regional impacts verify, and how quickly the event fades in 2027.
FAQs
Is El Niño happening now in October 2026?
Yes. NOAA has an El Niño Advisory in effect, and both oceanic and atmospheric indicators show a strongly coupled, rapidly intensifying El Niño.
How strong is the 2026 El Niño?
By mid-October it was already exceptionally strong by traditional weekly Niño-3.4 observations. IRI reported +3.3°C for the week centered October 14. NOAA's official RONI-based outlook gives an 83% chance that October–December reaches at least +2.5°C on the three-month RONI scale.
Is this a “super El Niño”?
That phrase is not a standardized scientific classification. It is fair to describe the event as very strong or potentially historic using a clearly identified index. This tracker avoids using “super” as though it were an official category.
When will El Niño peak?
The current consensus is late 2026. WMO's October 21 update projects the warming trend to peak around December, while some individual model systems indicate the event may already be near its maximum. Different metrics can peak at different times.
How long will El Niño last?
NOAA keeps El Niño near 100% probability through January–March 2027 and strongly favored into spring. Neutral becomes the most likely official NOAA category during April–June 2027.
Will El Niño make winter 2026–27 extreme everywhere?
No. El Niño shifts probabilities, not guarantees. Some regions are favored wetter, some drier, some warmer, and local weather can depart substantially from the canonical El Niño pattern.
Why are NOAA, IRI and WMO giving different temperature numbers?
They are not always measuring the same index, averaging period or forecast product. NOAA's official strength framework uses RONI; IRI prominently reports the traditional Niño-3.4 index; WMO publishes multi-model seasonal Niño-3.4 forecasts. Those values should always be labeled rather than directly ranked.
Could El Niño impacts continue after the SST index starts weakening?
Yes. Atmospheric teleconnections have seasonal timing, so winter circulation impacts can remain strong even after the tropical Pacific SST anomaly has passed its absolute peak.
Sources & update feed
- WMO Global Seasonal Climate Update — November 2026–January 2027, issued October 21, 2026. Latest international multi-model forecast; ~+3.8°C Niño-3.4 ensemble mean and December peak. WMO.
- IRI October 2026 ENSO Quick Look — October 19. Weekly Niño-3.4 +3.3°C centered October 14; 27-model plume and objective probabilities. IRI.
- NOAA CPC ENSO Diagnostic Discussion — October 8, 2026. Official El Niño Advisory, ocean/atmosphere observations and historic-strength probabilities. NOAA CPC.
- NOAA Official ENSO Probabilities — October 2026. RONI-based phase probabilities through mid-2027. NOAA CPC.
- NOAA Official ENSO Strength Probabilities — October 2026. Probabilities for weak, moderate, strong and very strong RONI categories. NOAA CPC.
- NOAA Official RONI Outlook — October 2026. Probabilistic Relative Oceanic Niño Index forecast ranges. NOAA CPC.
- WMO Global Seasonal Climate Update — October–December 2026, issued October 8. Forecast ~+3.7°C Niño-3.4 ensemble mean and late-2026 peak. WMO.
- WMO — Sea-surface temperatures reflect strengthening El Niño, October 8. Global summary of strengthening and expected temperature/rainfall impacts. WMO.
- NOAA GFDL — October 2026 El Niño Predictions, October 7. Experimental SPEAR forecast suggesting a near-term peak and spring/early-summer transition toward neutral. NOAA GFDL.
- NOAA — 2026–27 U.S. Winter Outlook, October 15. Temperature, precipitation and drought probabilities shaped heavily by the very strong El Niño. NOAA.
- NOAA CPC Long-Lead Seasonal Outlook — October 15. Technical discussion of U.S. seasonal outlooks and the role of the strengthening El Niño. NOAA CPC.
- WMO — El Niño influences South Asia winter climate outlook, October 14. Regional October–December precipitation and temperature outlook. WMO.
- WMO — El Niño looms large on World Food Day, October 16. Agriculture, fisheries, marine heat and food-security context. WMO.
- WMO — El Niño and South-West Indian Ocean hazards, October 1. Regional drought, flood, heat and cyclone outlook. WMO.
- NOAA CPC ENSO Diagnostic Discussion — September 10, 2026. Niño indices and greater-than-90% very-strong-event forecast. NOAA CPC current/archive access.
- WMO El Niño/La Niña Update — September 3, 2026. El Niño firmly established and near-100% persistence probability through February 2027. WMO.
- WMO Global Seasonal Climate Update — September–November 2026. Forecast ~+3.6°C seasonal Niño-3.4 ensemble mean. WMO.
- NOAA CPC ENSO Diagnostic Discussion — August 13, 2026. July Niño-3.4 +1.4°C and very large subsurface warming. NOAA CPC.
- WMO Global Seasonal Climate Update — August–October 2026, July 31. Strong El Niño developing; ensemble Niño-3.4 forecast near +2.9°C. WMO.
- NOAA CPC ENSO Diagnostic Discussion — June 11, 2026. El Niño Advisory issued; conditions declared present with weekly Niño-3.4 +0.7°C. NOAA CPC.
- NOAA Official ENSO Probabilities — June 2026 archive. Shows rapidly rising official probability of persistence through winter. NOAA CPC.
- NOAA CPC ENSO Diagnostic Discussion — May 14, 2026. El Niño Watch; ENSO-neutral observed but 82% May–July development probability and 96% winter persistence probability. NOAA CPC.
- NOAA Climate.gov ENSO hub. Definitions of Watch, Advisory and Final Advisory and links to operational ENSO monitoring. NOAA Climate.gov.
