El Niño Advisory · NOAA Climate Prediction Center
El Niño is active and strengthening
Very strong· conventional Niño 3.4Niño 3.4 conventional · weekly · threshold +0.5°C · week of October 21, 2026
The same ocean, two other methods
BOM relative Niño 3.4 · weekly · threshold +0.8°C · week ending October 25, 2026
official classification — NOAA RONI · seasonal · threshold ±0.5°C · JAS 2026
RONI subtracts the background warming of the whole tropical ocean, isolating El Niño's own signal — the gap between these numbers is the story, not an error. The two weekly readings are the cleanest apples-to-apples version of that same gap: same week, same cadence — +2.9°C once the tropics' shared warming is stripped out, versus +3.4°C raw. RONI is seasonal, so it covers a three-month period rather than a week and will always lag a fast-moving event.
What changed this week · Niño 3.4, NOAA conventional weekly
- this week, from +3.3°C to +3.4°C — the high of this event
- +0.1°C
- over four weeks, from +3.1°C on September 23, 2026
- +0.3°C
- above the +0.5°C El Niño line, since April 15, 2026
- 28 weeks
- warmest week in the series, which starts in 1981
- Record
What changed this week · Niño 3.4, NOAA conventional weekly
- this week, from +3.3°C to +3.4°C — the high of this event
- +0.1°C
- over four weeks, from +3.1°C on September 23, 2026
- +0.3°C
- above the +0.5°C El Niño line, since April 15, 2026
- 28 weeks
- warmest week in the series, which starts in 1981
- Record
- Outlook CPC's words: “El Niño will continue to strengthen through the end of the year”. Its latest discussion names no peak month, so neither do we.
- Strengthening through the end of the year
- Historic event Stronger than any El Niño since 1950 — meaning +2.5°C or more on the three-month RONI. CPC's figure is for October–December 2026; it gives 54% for September–November 2026 and 70% for November–January 2026–27.
- 83% · Oct–Dec 2026
- Strong to very strong A strong event means an anomaly of at least +1.5°C; very strong, at least +2.0°C. CPC calls a strong-to-very strong El Niño likely through January–March 2027 — a floor: CPC wrote “greater than”.
- over 83% · through Jan–Mar 2027
Outlook and odds: NOAA CPC ENSO Diagnostic Discussion of October 8, 2026 · full forecast
Right now, on the ground
Official notices that name El Niño, newest first.
- EmergencySep 22
California
30 days
Flood-insurance waiting period
Check flood cover before the storms, regulator says
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California's Insurance Commissioner asked residents to review their cover before the El Niño storm season. The release notes that homeowners, renters and commercial policies typically exclude flood damage, and that flood insurance generally takes effect 30 days after purchase.
- EmergencySep 21
California
75%
CPC odds of a historic Oct–Dec
State of emergency for El Niño preparedness
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California's governor proclaimed a state of emergency for El Niño preparedness. State agencies are to stage flood-fighting supplies such as sandbags and pumps; Caltrans is to stage road-closure and snow-removal equipment. The release cites NOAA's 75% chance of a historic event.
- EmergencySep 1
Peru
22
Departments covered (plus Callao)
60-day state of emergency over El Niño rains
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Peru declared a 60-day state of emergency in districts of 22 departments and the Constitutional Province of Callao, for imminent danger from heavy rain associated with El Niño 2026–2027. The decree is for risk reduction, response and rehabilitation measures.
- DroughtAug 20
Panama Canal
34, then 32
Daily transit slots
Fewer daily transits as watershed rain falls short
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The Panama Canal Authority cut daily transit slots to 34 for bookings from 4 September and to 32 from 15 September. Its advisory puts watershed rainfall since May 34% below the historical average and inflows 44% below, and names the 2026–27 El Niño as a reason the deficit could deepen.
- DroughtJul 6
Philippines
10
Provinces in meteorological drought
10 provinces in drought, 21 in dry spells
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PAGASA's El Niño Advisory no. 2 reported that, on rainfall to the end of June, 10 Philippine provinces were in meteorological drought and 21 under dry spells. It said El Niño was expected to become very strong by October–December 2026.
6 records broken by this event
2026 against the highest reading before it, same series
- Niño 3.4 · weeklyNOAA+3.4 °C+0.4 vs 2015
week of Oct 21
- Niño 3 · weeklyNOAA+4.3 °C+1.0 vs 1997
week of Oct 21
- Niño 1+2 · off PeruNOAA+5.3 °C+0.8 vs 1983
week of Sep 30
- Relative Niño 3.4 · weeklyBoM+2.88 °C+0.10 vs 2015
week to Oct 25
- ONI · JASNOAA+2.16 °C+0.37 vs 1997
JAS 2026
- MEI · Aug–SepNOAA PSL+2.37+0.13 vs 2015
Aug–Sep 2026
Computed from NOAA CPC weekly SST (wksst9120.for), Australian Bureau of Meteorology, rnino_3.4.txt, NOAA CPC Oceanic Niño Index (oni.ascii.txt), NOAA PSL MEI.v2 (meiv2.data). Weekly series week against week; ONI and MEI season against the same season.
Sea surface temperature anomalies, live
Warm water spreading along the equatorial Pacific is El Niño's signature
What this means where you are
Strong El Niño years land differently on every coastline — drought on one side of the Pacific, floods on the other. Pick your region for the honest historical picture.
What past super El Niños did to your state → interactive map
El Niño around the world
All regions
California
California's wettest winters cluster in strong El Niño years — and 2026–27 is forecast to be one of them.
Australia
Dry east, primed fuels, a wheat belt on edge — Australia faces the sharpest downside of a strong El Niño winter and spring.
India
A billion-person economy runs on four months of rain — and El Niño historically loads those months toward deficit. With famous exceptions.
Indonesia
The archipelago sits under El Niño's departing rains — drought, peat fires and regional haze are the historical price of a strong event.
Peru & South America
The place that named El Niño still takes its hardest punch: coastal floods, a collapsing fishery — and a wetter windfall far to the south.
Atlantic Basin
The one El Niño impact that arrives before winter: shear-suppressed Atlantic activity — with the 'it only takes one' asterisk written in 1992.
Vietnam
Drought in the Central Highlands hits the world's robusta supply; salt pushes up the Mekong Delta behind it.
Colombia
Dry season deepens, reservoirs fall, and the world's biggest washed-arabica crop takes the strain.
Argentina
One of the few countries where El Niño is usually good news — until the rain arrives at harvest.
East to west: all four Niño regions
Hottest off Peru, cooling westward — the classic strong El Niño shape. Tap a box for the map.
How to read this ▾Hide ▴
One number hides the structure. Niño 1+2 sits right off Peru and Ecuador, where this event is at its fiercest; the anomaly weakens westward toward Niño 4. That gradient — an eastern-Pacific-loaded event — is the classic strong El Niño picture.
Source: NOAA CPC weekly SST (OISST v2.1, 1991–2020 climatology). Conventional weekly anomalies vs the 1991–2020 climatology, week centered 21 Oct 2026 — the same file and baseline as the conventional weekly reading in the status panel, so the four figures are directly comparable. The BOM relative and RONI figures shown there are different indices and are not on this scale.
Is the event still being fed?
Still filling+3.39°Cwarm water below the surface, eastern Pacific · Sep 2026
How to read this ▾Hide ▴
Warm water piles up below the thermocline before it reaches the surface, so the upper-300 m heat content leads Niño 3.4 by one to three months. A reservoir that keeps filling means more warming is still to come; one that drains means the event is running out of fuel however warm the surface looks.
| Month | Whole basin | Eastern half |
|---|---|---|
| Apr 2026 | 1.85 | 2.24 |
| May 2026 | 1.67 | 1.99 |
| Jun 2026 | 1.79 | 2.26 |
| Jul 2026 | 2.03 | 2.96 |
| Aug 2026 | 2.19 | 3.23 |
| Sep 2026 | 2.23 | 3.39 |
Source: NOAA CPC equatorial upper-300 m mean temperature anomaly (1981–2010 climatology), 1979–present. Monthly, CPC; 1981–2010 climatology (the weekly Niño 3.4 uses 1991–2020 — compare directions, not absolute figures). Full depth structure: CPC GODAS.
The atmosphere's vote
Record for Aug–Sep+2.37Multivariate ENSO Index · Aug–Sep 2026
- 1982–83+1.68
- 1997–98+2.20
- 2015–16+2.24
- Now+2.37
How to read this ▾Hide ▴
The headline numbers read the ocean. MEI folds sea-surface temperature, sea-level pressure, surface winds and cloudiness into one figure, so it registers whether the atmosphere has joined the ocean. Each past event is compared at the same season.
Source: NOAA PSL Multivariate ENSO Index Version 2 (MEI.v2), 1979–present. Bi-monthly, updated monthly by NOAA PSL.
Has the atmosphere joined?
3 of 3 · coupled- Ocean+3.4°C✓ El Niño
- Pressure-2.0✓ El Niño
- Trade winds-5.3 m/s✓ El Niño
Ocean and atmosphere agree — the event feeds itself.
How to read this ▾Hide ▴
- Ocean · Niño 3.4 — surface warmth, the event itself · weekly
- Pressure · SOI — negative = Tahiti–Darwin see-saw on the El Niño side · Sep 2026
- Trades · 850 hPa west Pacific — negative = trade winds weaker than normal · Sep 2026
All three point the same way: the atmosphere has joined the ocean, which is what makes an El Niño self-sustaining rather than a warm patch of water.
Sources: CPC 850 hPa trade-wind index · CPC SOI · NOAA weekly SST. Wind and SOI are monthly, the ocean weekly. Data as of October 27, 2026
Global temperature × El Niño
+1.38°Cglobal mean, Sep 2026 · shaded = El Niño months
How to read this ▾Hide ▴
The hottest months on record cluster in and just after El Niño, and this event is unfolding on the warmest baseline ever measured.
Line: NASA GISTEMP v4, monthly global land–ocean anomaly vs 1951–1980. Bands: months NOAA's ONI puts at or above +0.5°C. Correlation shown, causation documented — El Niño redistributes ocean heat into the atmosphere. Data as of October 27, 2026
The 2026–27 event so far
Through Jan–Mar 2027
Strong to very strong
over 83% odds it stays strong or very strong (+1.5°C or more) through January–March 2027 — CPC, October 8, 2026.
Latest updates
All briefingsWeekly briefing · October 23, 2026
The El Niño Briefing #12: +3.3 °C again, and Niño 3 sets a new high
NOAA's weekly Niño 3.4 held at +3.3 °C for the week centred 14 October, level with the record set the week before. Further east, Niño 3 rose to +4.2 °C, a new high.
Weekly briefing · October 16, 2026
The El Niño Briefing #11: +3.3 °C, a third record week in a row
NOAA's weekly Niño 3.4 reached +3.3 °C for the week centred 7 October, the third record week in a row. The Bureau of Meteorology's relative index is at a record of its own, +2.81 °C.
Weekly briefing · October 9, 2026
The El Niño Briefing #10: +3.2 °C, and the odds of a historic event rise to 83%
NOAA's weekly Niño 3.4 reached +3.2 °C for the week centred 30 September, a second record week in a row. CPC's 8 October discussion puts the chance of a historic October–December at 83%, up from 75%.
CPC's current figures, each with its date, and every monthly analysis are on the forecast page.
The El Niño Briefing
One email a week while the event runs: the index moves that mattered, what changed in the forecasts, and one impact story explained.
Latest issue: +3.3 °C again, and Niño 3 sets a new high · all issues
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