El Niño forecast: where the official outlook stands
- When it peaks
- Strengthening through the end of the year
- CPC names no peak month · strong to very strong likely through Jan–Mar 2027 (over 83%)
- CPC outlook of October 8, 2026
- How strong
- 83% odds of a record
- stronger than any El Niño since 1950 in Oct–Dec 2026 (+2.5°C or more on the 3-month RONI) · 54% Sep–Nov 2026, 70% Nov–Jan 2026–27
- CPC outlook of October 8, 2026
- Right now
- +3.4°C
- weekly Niño 3.4, week of October 28, 2026 · very strong
The short version of the current El Niño forecast: El Niño Advisory is in effect, RONI — NOAA's official relative ENSO index — reads +2.0°C for ASO 2026, the conventional weekly Niño 3.4 anomaly is running at +3.4°C for the week centered October 28, 2026, and el niño conditions are present and strengthening. Official probabilities and every monthly update we've published since are below; the always-current numbers live on the dashboard, and every source behind them is documented on the data & methodology page.
The official CPC/IRI probability outlook
NOAA's Climate Prediction Center and the IRI issue a joint ENSO outlook around the second Thursday of each month, expressed as probabilities rather than a single prediction — the honest way to forecast a system with real uncertainty. CPC's discussion of October 8, 2026 gives 83% odds of a historic event in October–December 2026 — one exceeding every El Niño back to 1950, defined as +2.5°C or more on the three-month RONI, with 54% for September–November 2026 and 70% for November–January 2026–27. It calls a strong-to-very strong El Niño likely through January–March 2027, a greater than 83% chance. On timing, its words are “El Niño will continue to strengthen through the end of the year” — it names no peak month.
A "greater than" from CPC is a bound, not a point estimate: the real odds are higher than the number, not equal to it. And CPC did not restate everything on October 8, 2026, so the box above leaves out its older figures. The most recent of each, with the date CPC gave it: over 90% odds of a very strong event (at least +2.0°C) on September 10, 2026; 97% odds of El Niño persisting into early spring 2027 on July 9, 2026. We would rather date an older figure than present it as current.
Official ENSO outlook probabilities
Chance of each state by overlapping three-month season · CPC’s official ENSO probabilities, issued October 2026 (RONI-based)
83% odds that October–December 2026 beats every El Niño since 1950 (+2.5°C or more on the 3-month RONI); strong to very strong likely through January–March 2027 (over 83%) — CPC, October 8, 2026.
IRI's model plume of October 19, 2026 gathers 27 models (16 dynamical, 11 statistical), all of them forecasting a very strong El Niño (at least +2.0°C) from OND 2026 through DJF 2026–27; their combined average reaches about +3.5°C in October–December and November–January, on IRI's traditional Niño 3.4 index.
These are probabilities, not certainties — treat them as the current best odds, due to be revised at next month's outlook. See the 2026–27 event page for the full timeline and what strong-to-very-strong intensity has meant in past events.
What +2.0°C RONI means right now
RONI carries its own ±0.5°C thresholds — the same numbers as the conventional scale, just applied to the ocean's warmth relative to the wider tropics rather than to a fixed climatology. On that scale, +2.0°C for ASO 2026 reads very strong. The conventional weekly Niño 3.4 reading — +3.4°C for the week centered October 28, 2026 — sorts into bands the same way: neutral below +0.5°C, weak +0.5–0.9°C, moderate +1.0–1.4°C, strong +1.5–1.9°C, and very strong at +2.0°C or above — the tier reached only by 1982-83, 1997-98 and 2015-16 since 1950. The gap between the two readings is expected (RONI nets out the tropics' background warming), and the direction the event is moving — strengthening — matters as much as either number, since ENSO forecasts are ultimately a bet on trajectory, not a single snapshot. For the full mechanics of how these bands are defined, see the Niño 3.4 glossary entry.
Where is El Niño now?
The forecast odds above describe the ocean's trajectory; the live map shows its current location. Warm anomalies currently stretch as a ribbon along the equatorial Pacific, from the South American coast through the Niño 3.4 box that drives the headline number, toward the dateline. Panning the map week to week is the fastest way to see whether the event is still feeding — fresh warm water arriving from the west, ahead of the readings that will show up in next month's outlook.
See the live anomaly map →Heat below the surface
El Niño's fuel is warm water stored in the top 300 m of the equatorial Pacific. This index is the average temperature of that layer between 180° and 100°W, compared with normal for the month.
Same month in 1997: +2.56°C and 2015: +1.91°C.
Upper-ocean heat content, 2026 vs 1997 and 2015
Monthly anomaly, °C, Jan–Dec of each year · tap a year to hide or show it
What it means when this number falls
While the number climbs, warm water is still piling up below the surface and the event still has fuel. When it turns down, the stored heat is being spent — brought up to the surface and given off to the atmosphere, or carried away from the equator. In 1997 and 2015 this number turned down before the surface peaked (heat below: October 1997 and August 2015; surface Niño 3.4 monthly: November 1997 and January 2016) — so a sustained fall has meant the peak was near. In the comparison years: 1997 peaked at +2.56°C in October and read +1.02°C by December; 2015 peaked at +1.97°C in August and read +1.20°C by December. In 2026 it was flat in October.
Where the heat sits: the equator, surface to 300 m
The same layer drawn as a slice along the equator, from Indonesia on the left to South America on the right, surface at the top. Red is warmer than normal for the month, blue colder. A downwelling Kelvin wave shows up as a warm patch below the surface that travels east and rises toward it from one month to the next — step through the months to follow it.
Latest value as published by NOAA CPC (file last modified November 4, 2026), downloaded November 4, 2026. Anomalies are against the 1981–2010 climatology, a different baseline from the 1991–2020 one behind the weekly Niño 3.4 value — compare directions, not absolute figures across the two. The slice above steps a month at a time; CPC draws the same kind of section every five days in its GODAS pentad pages.
Monthly forecast updates
One analysis after each official monthly outlook: how the odds moved, what the models converged on, and what to watch next.
July 9, 2026
NOAA Raises the Odds of a Very Strong El Niño to 81%
The July outlook jumps very-strong odds from 63% to 81%, centers the peak on Oct–Dec 2026 — and the ocean is running ahead of 1997 and 2015.
June 12, 2026
NOAA Declares El Niño — and the Odds of a Very Strong Event Rise
The Advisory is official: ~100% odds El Niño lasts through the Northern Hemisphere winter, 88% at least strong, 63% very strong. How June 2026 compares to 1997 and 2015.
May 14, 2026
El Niño Has Arrived: The Pacific Crosses the Threshold
Weekly readings have crossed the +0.5°C line for the first time since the La Niña ended. Here's what must happen before an official declaration.