Current Conditions
Auto-updates on page load · NOAA CPC ONI · ERSST v5
I AM HERE
El Niño Advisory
· official CPC wording · issued 13 August 2026
Declared by CPC forecasters, not derived from a single index crossing a threshold. Next Diagnostic Discussion 10 September 2026.
What changed in the latest update
Recomputed from the NOAA source files listed below. Seasonal values last verified against NOAA on 5 August 2026; weekly values are verified through the week centred 12 August 2026. Next scheduled change: the CPC ENSO Diagnostic Discussion on 13 August 2026.
- Seasonal RONI rose +0.49 °C in one season, from +0.49 °C in AMJ 2026 to +0.98 °C in MJJ 2026. That is the season in which the official relative index crossed the +0.5 °C El Niño threshold. calculated from RONI.ascii.txt (ERSSTv6)
- Conventional ONI rose +0.44 °C over the same seasons, from +0.95 to +1.39 °C. The two indices are not disagreeing about the ocean: RONI subtracts the tropical-mean anomaly, so it reads lower in a warm tropical year. calculated from oni.ascii.txt (ERSSTv6)
- The gap between them narrowed slightly, from 0.46 to 0.41 °C. This is a difference this site calculates; NOAA publishes the two series separately and does not publish the spread. A narrowing gap means Niño 3.4 is warming faster than the tropical mean. derived on this site from the two CPC files above
- The basin is strongly east-weighted. For the week centred 12 August 2026 the relative anomalies were Niño 1+2 +3.2, Niño 3 +2.5, Niño 3.4 +1.8 and Niño 4 +0.2 °C, an east-to-west spread of 3.0 °C across the basin. calculated from rel_wksst9120.txt
- The same week reads +2.3 °C on the conventional weekly table against +1.5 °C on the relative one, an offset of 0.8 °C. Both files are live and both are correct. A near-uniform offset across all four regions is the signature of an index difference, not a data revision. compared against wksst9120.for
- The MJO is not currently contributing. NOAA PSL ROMI amplitude was 0.13 on 31 July 2026, far below the 1.0 activity threshold, so the phase number carries no reliable interpretation and no MJO-driven acceleration should be read into the trend. NOAA PSL ROMI
What would change this reading. If the 13 August CPC discussion puts JJA 2026 RONI below +0.98 °C, the one-season acceleration above has stalled. If the weekly Niño 4 anomaly turns negative while Niño 1+2 holds above +3 °C, the event is becoming more sharply east-based than the current spread implies. Either outcome is visible in the two CPC files linked above without waiting for interpretation.
Observations and calculated differences only. Nothing in this section is a forecast. Forecast probabilities are shown separately, lower down, and are labelled with the agency that issued them.
Seasonal RONI
+0.98°C
relative · 3-mo season · MJJ 2026 · above +0.5°C (was +0.49 in AMJ)
Traditional ONI
+1.39°C
conventional · 3-mo season · MJJ 2026 · historical reference
Weekly Niño 3.4 pulse
+1.80°C
relative · 1 week · centered 12 Aug 2026
Season
MJJ 2026
overlapping 3-mo period
6-Month Trend
+1.53°C
vs OND 2025
Threshold Streak
2
seasons at ±0.5°C
ONI and RONI both verified for MJJ 2026. ONI +1.39°C (conventional, oni.ascii.txt (ERSSTv6)) and RONI +0.98°C (relative, RONI.ascii.txt (ERSSTv6)), both verified 5 August 2026. NOAA revises prior seasons, so earlier values can change after publication.
These are four different measurements, not four views of one number.
The seasonal RONI averages three months, so it lags a fast-developing
event: it was still +0.49 in AMJ 2026 while CPC's El Niño Advisory
was already active, and only crossed +0.5°C in MJJ 2026 (+0.98). A
seasonal index sitting below its threshold never contradicted the
Advisory, because CPC declares status on the full picture rather than on
one index. The weekly pulse is a single week and moves first of all.
Official data
Where El Niño Stands
Dated static summary, written against the week centred 12 August 2026. It does not auto-update; the live panels below refresh independently on every page load.
NOAA's Climate Prediction Center is carrying an El Niño Advisory. In its discussion of 13 August 2026, CPC reported July monthly values of +1.4°C in Niño 3.4, +1.7°C in Niño 3 and +2.9°C in Niño 1+2, and stated that El Niño is strengthening. Its season-by-season strength table now puts a 95% probability on a very strong event during October to December, up from 81% in the July issuance. CPC separately assigns a 69% probability to a historic event in that season, which it defines as a three-month RONI value of +2.5°C or more, a level that would exceed every El Niño since 1950. What +2.5°C would actually have to beat →
For the week centered 12 August 2026, the weekly relative values were Niño 1+2 +3.2°C, Niño 3 +2.5°C, Niño 3.4 +1.8°C and Niño 4 +0.2°C. These are relative-index values (tropical-mean anomaly removed) and are not comparable with conventional weekly values, which run roughly 0.8°C higher.
The official seasonal RONI stands at +0.98°C for May to July 2026, against a traditional ONI of +1.39°C for the same season (in April to June the pair was +0.49 and +0.95). RONI is a three-month running mean and lags the weekly readings, which is why the seasonal index can sit below the +0.5°C threshold while a strengthening El Niño is already underway. The two indices differ because RONI subtracts the tropical-mean anomaly and then applies variance-restoration scaling, so the gap between them is not a disagreement about the ocean. Why CPC and IRI publish different Niño 3.4 numbers →
Values in this summary are static, reflect the observation week named above, and do not refresh. The dashboard below refreshes from NOAA CPC on every page load. Weekly figures update each Monday and are subject to revision. Sources: CPC ENSO Diagnostic Discussion, 9 July 2026 and CPC weekly relative SST table.
Every article is written against the primary NOAA source files, carries the date and data vintage it was current as of, and is written and meteorologically reviewed by Christopher W. Corwin, B.S. Meteorology.
ENSO Flavor
Site-calculated: Eastern Pacific vs Central Pacific vs Basin-Wide vs Coastal
El Niño is not one thing. Eastern-Pacific (EP) events warm the far eastern Pacific and tend to produce stronger drought teleconnections. Central-Pacific (CP / Modoki) events warm near the dateline and have different global impacts. The Trans-Niño Index (TNI) captures the SST gradient between east and central Pacific. The flavor result below is calculated on this site from weekly Niño-region anomalies. It is not a NOAA product, and it is not an ENFEN El Niño Costero declaration — that is an official Peruvian regional status which can coexist with a basin-wide El Niño and cannot be inferred from weekly SST arithmetic alone.
ENSO Flavor (site-calculated)
EASTERN-PACIFIC-DOMINANT
Site-calculated current weekly SST pattern · one weekly four-region observation, week centered 12 Aug 2026 · not a formal or seasonally established event classification · fallback: last verified 12 August 2026; live refresh unavailable.
Trans-Niño Index
+2.38
Niño 1+2 minus Niño 4 (normalized) · site-calculated
EP Signal
+2.85°C
Niño 1+2 + Niño 3 avg · site-calculated
CP Signal
+1.00°C
Niño 3.4 + Niño 4 avg · site-calculated
Niño Region Anomaly Comparison: Flavor Profile
Coupling Checklist
Is the ocean actually talking to the atmosphere?
Warm water alone is not a fully coupled El Niño. The Bjerknes feedback loop requires the atmosphere to respond: trade winds weaken, convection shifts east, Walker Circulation disrupts. All six conditions locking in together is what makes events like 1877 catastrophic.
MJO Assist
Madden-Julian Oscillation · NOAA PSL ROMI · RMM octant convention
The MJO is an eastward-traveling pulse of tropical rainfall and wind that circles the globe every 30–60 days. When its active phase sits over the Maritime Continent / western Pacific (roughly phases 5–7), it can fire off westerly wind bursts, short bursts of west wind that push warm water eastward and can kick off a downwelling Kelvin wave. That's one of the main ways El Niño gets a head start. The MJO doesn't cause El Niño on its own, but an active MJO in the right spot can load the dice.
RMM Phase
(3)
1–8 · convection location
Amplitude
0.13
≥1.0 = active MJO · observed 31 Jul 2026
MJO Status
INACTIVE / WEAK
phase not meaningful below 1.0
active / weak / inactive
ENSO Assist
LOW
favors WWB / Kelvin wave?
RMM Phase Diagram: last 40 days
MJO is weak or inactive (amplitude 0.48), no strong atmospheric "kick" toward El Niño development from the MJO at the moment. Other drivers (background trades, WWBs from other sources) still apply.
Source:
NOAA PSL ROMI, projected onto the Wheeler-Hendon octant convention for phase numbering. ROMI and the BOM Wheeler-Hendon RMM are
related but distinct products and are not interchangeable; they use different input fields and filtering and can differ in phase and amplitude on the same day. When amplitude is at or above 1.0, phases 5–7 place convection over the Maritime Continent and western Pacific, which
historically raises the odds of westerly wind events; it does not guarantee one, and below amplitude 1.0 the phase carries no reliable interpretation
. Legacy note: Phases 5–7 = western Pacific / Maritime Continent convection, most relevant to ENSO · MJO forecast skill ~2–3 weeks, this is a current-conditions read, not a seasonal forecast.
Relative ONI (RONI)
NOAA CPC Official Index · Replaced ONI Feb 2026 · Tropical-mean adjusted
NOAA officially replaced the ONI with the RONI on February 1, 2026. RONI subtracts the average SST anomaly across the entire tropical belt (20°S–20°N) from the Niño 3.4 anomaly, then scales to match ONI variance. This removes background warming trends from climate change, making historical event comparisons more consistent. The ±0.5°C threshold still applies.
Current RONI
+0.98°C
official NOAA CPC value (°C)
RONI vs ONI
-0.41°C
difference (tropical mean removed)
RONI vs its threshold
ABOVE +0.5°C THRESHOLD
index vs its own threshold, not an event classification
Seasonal Context
+0.89σ ⚡
normalized ONI (our calculation)
RONI Distribution: Current season vs. historical range
Computed from NOAA CPC ONI 1950–present · Seasonal std dev calculated across all years · Spring (FMA–MAM) has lowest variance = spring predictability barrier
Weekly SST Pulse
NOAA CPC · All 4 Niño regions · Updates every Monday
Niño 1+2 (E. Pacific)
+3.20°C
weekly SSTA °C · coastal Peru
Niño 3 (E. Central)
+2.50°C
weekly SSTA °C · 5°N–5°S 150°–90°W
Niño 3.4 ← Primary
+1.80°C
weekly SSTA °C · ONI source region
Niño 4 (Central)
+0.20°C
weekly SSTA °C · 5°N–5°S 160°E–150°W
Week centered 12 August 2026 · Official data · NOAA CPC weekly relative Niño index · rel_wksst9120.txt
Niño 1+2
Niño 3
Niño 3.4
Niño 4
Last 52 weeks · NOAA CPC OISST-based weekly SST anomalies · All four Niño monitoring regions · Week centered 12 August 2026
Atmospheric Coupling
SOI · Trade Winds · Walker Circulation · NOAA PSL
The Southern Oscillation Index (SOI) measures atmospheric coupling: the pressure difference between Tahiti and Darwin. Negative SOI confirms El Niño is forcing the atmosphere, not just warming the ocean. When both ONI and SOI align, the event is real.
Monthly SOI
-4.0
standardized (σ) · July 2026 · negative = El Niño-like
SOI Trend
-1.6
vs June 2026 (-2.4)
Coupling Status
SOI SIGN CONSISTENT
Derived SOI + RONI only
Walker Circulation
SOI-CONSISTENT ONLY
Derived no wind or OLR feed ingested
SOI (monthly)
±0.5 threshold
Source:
NOAA PSL standardized SOI (computed by NOAA CPC) · monthly means, scale approx −6 to +6 · latest July 2026 = −4.0 ·
not the BOM Troup SOI, which runs approx −35 to +35 · negative = weakened Walker Circulation / El Niño-like
Niño 3.4 SST Spaghetti Chart
Weekly Relative Anomaly · Every Year Since 1981 · NOAA CPC
Weekly relative Niño-3.4 SST anomaly (RONI methodology), every year since 1981 plotted as a thin grey line, current year and the 1997 / 2015 super-event analogs highlighted for comparison.
Latest Reading
+1.80°C · week centered 12 Aug 2026 · fallback: last verified 12 August 2026; live refresh unavailable.
All years (1981–present)
1997
2015
Current year
Source: NOAA CPC Relative Weekly SST (rel_wksst9120.txt) · Auto-updates weekly (Mondays) · Relative anomaly = RONI-consistent
Subsurface Ocean State
Not assessed · no independent subsurface dataset ingested
SUBSURFACE STATE: NOT ASSESSED. No independent subsurface dataset is currently ingested. Surface Niño 3.4 cannot establish ocean heat content, recharge state, Kelvin-wave activity or Bjerknes feedback. The NOAA links below are surface SST reference maps and do not provide subsurface data.
Heat Content Anomaly
NOT ASSESSED
requires a 0–300 m heat-content feed; none ingested
Recharge State
NOT ASSESSED
requires warm-water-volume data; none ingested
1877 Context
HISTORICAL NOTE
1877 is reported to have had a large warm-water buildup before its peak. Historical context only, not a current measurement.
Bjerknes Feedback
NOT ASSESSED
Bjerknes feedback is an ocean-atmosphere coupling mechanism. It cannot be established from surface SST, or from two indices carrying opposite signs. Requires wind, convection and subsurface fields this site does not ingest. See NOAA CPC for the official coupled diagnosis.
PACIFIC SST ANOMALY MAP · VIEW AT THE SOURCE
This panel links to NOAA's Pacific SST anomaly products rather than mirroring the weekly
image. The CPC image was last confirmed to contain a plotted grid on
2 August 2026;
an HTTP 200 response and valid dimensions do not establish that a chart contains data, and this site
does not republish an agency image it cannot verify. The two links below always show the current product.
Source: NOAA CPC and NOAA OSPO · Pacific SST anomaly · normally updated weekly.
The numeric equivalent of this map, region by region, is in the weekly SST panel above and in the
east-west gradient analysis.
Historical Event Comparison
2026 vs. Major El Niño Events, ONI Trajectory · 2026 line is live to the latest verified season; analog lines are static
Each event anchored to January of the onset year. The 1877–78 reconstruction uses ERSSTv5 ONI-style retrospective estimates (±0.5°C uncertainty). Modern events use operational NOAA ONI. The spring predictability barrier (boreal spring) limits forecast skill, events that survive April tend to peak strongly.
All Events
1877–78
1982–83
1997–98
2015–16
2026 Only
1877–78 (reconstructed)
1982–83
1997–98
2015–16
2026 (current, through latest verified season)
Month 1 = January of onset year · 1877 solid line = ERSSTv5 reconstruction (~3.5°C peak) · 1877 dashed = possible true peak (~4.5°C) accounting for sparse 19th-century ship observations · Modern events use operational ONI · Huang et al. (2020): 1877 amplitude likely underestimated due to sparse data
~3.5°C Peak (ERSSTv5 Niño-3)
The strongest pre-satellite El Niño on record. Coincided with record positive IOD and warm North Atlantic. Triggered the Great Famine of 1876–78, Grande Seca, and Northern Chinese Famine, 50M+ deaths globally.
Duration: ~18 months · Peak: Oct–Dec 1877 · Classification: Extreme
Peak ONI: +2.1°C · Peak Niño-3.4 SST Anomaly: +4.1°C
The first "super" El Niño of the satellite era. Caught forecasters off guard, models failed to predict it. Severe drought in Australia, India, and Africa; catastrophic flooding in Peru and Ecuador.
Duration: 14 months · Peak: Oct 1982 · $13B damage (1983 dollars)
Peak ONI: +2.4°C · Peak Niño-3.4 SST Anomaly: +4.56°C, Largest Modern Record
The strongest El Niño in the modern instrumental record by ONI. Rapid onset from spring, explosive growth through summer. Massive fires in Indonesia, drought across Africa and Asia, record flooding in California.
Duration: 13 months · Peak: Nov 1997 · ~$100B global damage
Peak ONI: +2.6°C · Peak Niño-3.4 SST Anomaly: +4.45°C
The second strongest modern El Niño, nearly matching 1997–98. Record coral bleaching on the Great Barrier Reef. Severe drought across Eastern and Southern Africa. California received above-normal rainfall for the first time in years.
Duration: 15 months · Peak: Oct–Nov 2015 · Widespread global impacts
Ways the 1877 Analog Breaks
Scientific honesty, what would falsify this comparison?
The 1877 analog is historically interesting, not deterministic forecasting. These conditions would break the comparison:
⚠ Westerly Wind Bursts Stop
If WWBs cease and trade winds reassert, the Bjerknes feedback loop breaks. The Pacific can revert to neutral without the atmospheric coupling that made 1877 extreme.
⚠ Subsurface Heat Discharges Early
If the warm water volume discharges before peak season, the fuel for intensification is gone. The 2014 event stalled exactly this way, a strong easterly wind burst in June discharged the heat reservoir.
⚠ Niño 1+2 Cools, Niño 4 Dominates
If warming shifts from eastern to central Pacific, the flavor becomes CP/Modoki, a fundamentally different event with weaker and different teleconnections. 1877 was strongly EP-flavored.
⚠ SOI Fails to Hold Negative
If the SOI returns to positive or neutral, the Walker Circulation has not broken down. Ocean warming without atmospheric coupling is not a fully-coupled El Niño, and 1877's devastation required full coupling.
⚠ IOD Remains Neutral or Negative
The 1877 event was amplified by a record-strong positive IOD and warm North Atlantic. If the IOD stays neutral or goes negative, a key amplifier of the historical drought teleconnections is absent.
⚠ Model Spread Widens After Peak
If the CCSR/IRI objective model ensemble diverges significantly, high spread, low agreement on amplitude, forecast confidence drops. Current 97–98% probabilities assume model agreement holds through 2026.
CONFIDENCE BADGE: SITE-CALCULATED ANALOG, NOT AN OFFICIAL PRODUCT ·
1877 reconstruction: ERSSTv5 ±0.5°C uncertainty ·
This comparison is historically interesting, not operational forecasting ·
Singh et al. (2018) · Huang et al. (2020)
Event Log
Threshold crossings recorded this session
MJJ 2026Seasonal RONI crossed +0.5°C, reaching +0.98°C after +0.49°C in AMJ 2026. Verified against NOAA CPC RONI.ascii.txt on 5 August 2026. Further entries are added in-session as the live indices cross threshold levels.
1877–78 Analog Score
How close are we to the Niño of all Niños?
A weighted comparison of the current ENSO state against the 1877–78 event, calculated on this site. Not an operational NOAA product. Historical values from ERSSTv5 reconstruction, treat as probabilistic, not definitive. Huang et al. (2020) notes ±0.5°C uncertainty on 1877 peak.
1877-Style Analog Score
Calculated on load
Calculating…
1877 PEAK REF
~+3.5°C
ERSSTv5 Niño-3
ONI vs. 1877 Trajectory
Current event overlaid on the 1877–78 analog (Jan = event year start)
1877–78 (reconstructed)
Current event
±0.5°C uncertainty
1877 values: ERSSTv5 ONI-style retrospective reconstruction. Dashed = current. Shaded = ±0.5°C cross-dataset spread.
El Niño ≥+0.5°C
La Niña ≤−0.5°C
Neutral
What Happened Last Time
1876–79 documented ground-level impacts
Catastrophic Monsoon Failure
Indian Summer Monsoon failed across the Deccan Plateau and spread northward. Total crop failure in many districts over two consecutive years.
Great Famine 1876–78 · 5.6–9.6M deaths · Madras, Bombay, Mysore, Hyderabad
Multi-Year Drought & Crop Collapse
Shanxi, Henan, Shaanxi, Zhili, and Shandong suffered devastating rainfall deficits. Known as the "Incredible Famine."
Northern Chinese Famine 1876–79 · 9–13M deaths · North China Plain
Grande Seca, The Great Drought
Complete rainy season failure across the Nordeste. Rivers dried entirely. The Sertão interior became uninhabitable for millions.
Grande Seca · 500K–1M deaths · Ceará, Pernambuco, Piauí, Paraíba
Widespread Rainfall Deficits
Drought across Ethiopia, Egypt, and the Sahel. Livestock losses and crop failures compounded colonial-era food insecurity.
Concurrent famines across East Africa · Estimates uncertain · Ethiopia, Egypt, Sahel
Severe Inland Drought
Eastern and interior Australia experienced significant rainfall deficits. Pastoral industries suffered heavy livestock losses across Queensland and NSW.
Significant agricultural losses · Queensland, NSW, Victoria
Year Without a Winter
Exceptionally mild winter 1877–78. El Niño typically brings warmer, drier winters to the northern US and wetter conditions to the Gulf Coast and California.
No major mortality · "Year Without a Winter" · Northern U.S. and Canada
Extreme Coastal Flooding
El Niño's home turf, extreme coastal SST warming, heavy rainfall, flooding of normally arid coastal deserts, and fishery collapse.
Severe coastal flooding · Fishery collapse · Niño 1+2 region
Monsoon Suppression & Drought
Convection shifts east, suppressing rainfall over the Maritime Continent. Wildfire risk rises dramatically across Indonesia and the Philippines.
Severe drought across Indonesia & Philippines · Widespread crop failures
El Niño Forecast
CCSR/IRI objective model phase probabilities · published 20 July 2026 · monthly
El Niño Probability
100%
JAS 2026 through JFM 2027
El Niño is established and strengthening. CPC's 13 August discussion reported July monthly values of +1.4°C in Niño 3.4 and +2.9°C in Niño 1+2, and its strength table raised the October–December very strong probability to 95%. CPC also assigns a 69% chance of a historic event in October–December, defined as a three-month RONI value of +2.5°C or more. The latest verified weekly relative Niño 3.4 value on this site is +1.8°C for the week centered 12 August 2026. Note that CPC quotes the relative index while IRI quotes the traditional Niño 3.4 index, so the two publish different values for the same week.
Forecast Issued
published 20 July 2026
Source
CCSR/IRI ENSO Plume · objective model
1877 Context
1877 peaked at ~3.5°C ONI. Current trajectory bears watching.
El Niño probability
Neutral probability
La Niña probability
Source: CCSR/IRI objective ENSO probability forecast (Columbia) · issued 20 July 2026 · phase probabilities, bars sum to 100% per season · not CPC’s official forecaster probabilities ·
IRI Quick Look →
CPC persistence probability
97%
Official El Niño persisting through early spring 2027 · Diagnostic Discussion, issued 9 Jul 2026 · not restated in the 13 Aug discussion, so this remains the most recent published persistence figure · not a seasonal histogram
CPC strength probability
95%
Official very strong event, RONI ≥ +2.0°C · Oct–Dec 2026 · issued 13 Aug 2026 · was 81% in the July issuance
IRI objective phase probability
100%
Objective model El Niño · JAS 2026 through JFM 2027 · 99% FMA 2027, 94% MAM 2027 · published 20 Jul 2026
IRI model-count strength
23 of 26
Objective model models forecasting very strong (Niño 3.4 ≥ +2.0°C) at the OND 2026 peak · a count, not a probability
Model plume / means
NOT INGESTED
individual traces, dynamical and statistical means are not fetched
These are different products, not competing versions of one number.
CPC's official outlook can incorporate expert forecaster judgement; IRI's is
objective model output, so the two can differ without either being wrong.
A phase probability answers "which state?" and a strength
probability answers "how strong, if El Niño?" . They are not comparable. None of these is an observed index: a forecast probability is a
statement about the future, while RONI and the weekly pulse above are
measurements of what already happened. Every percentage here is tied to a
named season; a bare "97% El Niño" would be meaningless without one.
Seasonal ONI Table
Last 10 years · °C anomaly
Seasonal ONI table, built from the primary-verified NOAA history. Latest verified season MJJ 2026 = +1.39°C (conventional). Source: oni.ascii.txt (ERSSTv6), verified 5 August 2026.