{"data":{"id":"el-ni-o-the-pacific-warming-that-shifts-world-weather-breaks-3e7f96","slug":"el-ni-o-the-pacific-warming-that-shifts-world-weather-breaks-3e7f96","title":"El Niño, the Pacific warming that shifts world weather, breaks its daily heat record","dek":"The monthly record still stands, but all 674 forecasts point to a winter peak beyond any since 1877 — at a size no seasonal system has been tested against and after summer runs came in 0.3C too warm.","published_at":"2026-10-03T23:21:08.861617+00:00","status":"publishable","tags":["science","NOAA Climate Prediction Center (CPC)","World Meteorological Organization (WMO)","El Niño-Southern Oscillation (ENSO)","Niño 3.4 region"],"places":["United States"],"quick_take":{"whatHappened":"El Niño's benchmark Niño 3.4 box hit 3.11C above normal on 21 September, topping the 2015 daily high, while the monthly mean for August at 2.45C remains below the all-time monthly record and 674 model runs point to a November-January peak around 4.1C.","whyItMatters":"The lagged heat makes 2027 likely to be the warmest year on record and tilts odds for drought, floods and extreme heat worldwide, though a stronger El Niño does not mean worse impacts where you live.","whatIsUncertain":"Whether that forecast peak verifies at a size no system has been tested against after summer runs came in 0.3C too warm, and whether the cleaner Relative ONI measure also tops its 1982 record."},"markdown":"The central Pacific was 3.11C warmer than normal on 21 September, beating the daily high of 3.08C set in November 2015. The reading comes from El Nino's benchmark box in the central-eastern equatorial Pacific, and forecasts point higher — toward a monthly peak that would dwarf any event in 150 years, if it verifies at a size no system has been tested against.\n\nThat box is the Nino 3.4 region, a rectangle straddling the equator (170W-120W, 5S-5N). El Nino — the periodic warming there that shifts weather worldwide — is judged by how warm that box is, and by which ruler you use to strip out the background warming of the oceans. The choice decides whether this is already the strongest on record and what its heat means for global temperature and for drought, flood and extreme heat.\n\n## A daily record, not yet a monthly one\n\nThe 3.11C is a daily Nino 3.4 anomaly calculated the way NOAA's Oceanic Nino Index (ONI) does it — sea-surface temperature minus a centred 30-year average — applied day-by-day to NOAA's OISSTv2.1 sea-surface dataset by Carbon Brief, the UK climate news site.\n\nThat is not the operational ONI, which is a three-month rolling mean, and it is not the monthly record. August averaged about 2.45C for the month. That already beats every El Nino except 2015-16 and the sparse reconstruction of 1877-78, but remains below those peaks.\n\nThe timing matters. El Nino typically peaks in November or December, and every strong event on record kept strengthening after mid-September. At 3.11C daily and 2.45C monthly, this one is already well into very strong territory.\n\n## Why two rulers give two answers\n\nWhether 2026 is the \"strongest on record\" depends on how you remove the warming of the oceans themselves.\n\nONI subtracts the latest centred 30-year average in the Nino box. In a warming world that leaves a bias: it tends to inflate El Nino and understate La Nina, because the whole tropical ocean is warmer than 30 years ago.\n\nThe Relative ONI (RONI), adopted by the US Climate Prediction Center in February 2026, tries to isolate the El Nino-driven part. It subtracts the average anomaly across the entire tropical ocean between 20N and 20S, not just the 30-year mean in the box. NOAA says it matches observed impacts like drought better, though some researchers argue it may understate warming-driven impacts. The debate is active.\n\nOn that second ruler the picture shifts. Daily RONI stood around 2.5C in mid-September, a record for the time of year but still about 0.7C below the all-time daily RONI peak in late December 1982. The 2023-24 El Nino shows why it matters: it peaked around 2.0-2.1C on ONI but only about 1.5C on RONI, borderline strong.\n\nNeither ruler is wrong. ONI is the long-standing standard for ranking events back to 1950 and, with reconstructions, to 1877. RONI is what the US centre now uses to judge strength and forecast impacts, because it gives a cleaner read on how much warmth is actually driving the atmosphere. On ONI, 2026 has already broken the daily record and is closing on the monthly one. On RONI, it is record-strong for September but not yet all-time.\n\n## How it got hot — and how high forecasts point\n\nThe World Meteorological Organization and the US Climate Prediction Center point to the same fuel: exceptionally warm water at the surface and even warmer water below, plus an atmosphere that has locked in.\n\nWeekly Nino 3.4 values rose from about 1.5C in May-July to 2.2-2.6C by mid-August. Below the surface, temperatures were more than 8C above average in July and early August, with even larger anomalies at depth, according to secondary summaries of the agencies' diagnostics.\n\nThat heat reservoir fuels feedback that reinforces warming. A developing positive Indian Ocean Dipole — a periodic warming in the western Indian Ocean that can reinforce El Nino — forecast around 0.9C for September-November, is adding to the loop. The Nino 3.4 index crossed 0.5C in April, hit 1.6C in June and shot above 2C in early July, outpacing any prior event's development. No peer-reviewed study yet quantifies how much human-caused warming contributed to the 3.11C versus natural variability.\n\nWhat makes this more than a daily record is the unanimity and margin of the forecast for the monthly peak in November to January. Carbon Brief's analysis of 14 modelling groups (674 runs) puts the median monthly ONI peak around 4.1C, with 80% of runs between 3.4C and 4.6C. Every run peaks above the 2015-16 monthly record of 2.75C.\n\nOn RONI the same ensemble still points to a record, but less unanimously: median around 3.1C versus the 1982-83 RONI record of 2.69C, with 77% of runs breaking it. The Climate Prediction Center's outlook mirrors that strength: for October-December it gives a 98% chance of very strong (above 2C on RONI) and a 75% chance of historic strength above 2.5C, a level that would exceed every event since 1950.\n\nNo seasonal system has been verified against an event this large, because none has occurred, and models ran warm this summer — August came in about 0.3C below forecasts. All strong El Ninos on record did keep strengthening after mid-September, which supports further intensification, but the exact peak and whether RONI also falls remain open.\n\n## Why 2027 carries the heat\n\nEl Nino-Southern Oscillation (ENSO) is the largest year-to-year driver of global mean temperature, but its effect lags the ocean by months. Heat stored in the Pacific leaks into the atmosphere after the ocean peaks, so the warmest year typically follows the El Nino winter.\n\nThat lag is why 2026 and 2027 look different. The first six months of 2026 were the third-warmest January-June on record, about 1.4C above pre-industrial levels, behind only 2024 and 2025. Carbon Brief's central estimate still has 2026 at about 1.51C, with a 35% chance of beating 2024 as the warmest year — up from 19% in April — but whether it sets a record will depend on the dataset.\n\nFor 2027 the signal is clearer. Carbon Brief projects around 1.7C above pre-industrial, which would comfortably set a new warmest-year record, because the ocean peak in late 2026 would be felt most the following year. The WMO's September-November outlook already favours above-normal temperatures across almost all land areas.\n\nA very strong El Nino tilts the odds for rainfall and temperature far from the Pacific — what scientists call teleconnections — but strength alone does not determine severity in any single country. Other basins modulate the signal.\n\nFor September-November and into the boreal winter, the classic risk pattern flagged by WMO and the inter-agency Global ENSO Analysis Cell includes drought across several tropical regions and floods in parts of South America, plus extreme heat and wildfires elsewhere. The concurrent Dipole and warmer tropical Atlantic may alter those links in different regions.\n\nThe humanitarian exposure is framed as probability, not observed disaster. Both the estimate that up to 50 million people could be affected and the projection of about 451,000 excess deaths by February 2027 are model-based projections reported via ReliefWeb, not observed counts, and carry wide uncertainty.\n\nForecasters put near-certain odds on El Nino persisting through the northern winter — WMO near 100% through February 2027 and the US centre at 100% through December-February — with no dynamical signal for a flip to La Nina before spring. In the longer term history points the other way as precedent, not forecast: all five super El Ninos since 1970 collapsed quickly to neutral or La Nina after their peaks, a pattern cited as a reason to watch for a swift transition in mid-2027.\n\nWhat remains open is whether the monthly ONI record falls and by how much, whether RONI also breaks its 1982 highs, how the Dipole and warm Atlantic reshape the regional odds, and how much of the 3.11C reflects human-caused warming versus natural variability — a question for which no peer-reviewed attribution study yet exists.","receipts_markdown":"**How this piece is framed:** A record-breaking Pacific warming event, measured two ways, forecast to go much further — and what that does and does not mean for world heat and regional weather\n\n**Visuals not shipped** — _planned but not fulfilled_\n- 2026 El Niño already a daily record — forecast to shatter the monthly record: could not be produced for this edition\n- Where a very strong El Niño tilts the odds toward drought, floods and heat: could not be produced for this edition\n\n**Sources**\n- (primary) Official NOAA CPC ENSO Probabilities - September 2026 — NOAA Climate Prediction Center — https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/probabilities  ·  _read in full · captured 2026-10-03_\n- (primary) Global Update September 2026: El Niño Status & Humanitarian Outlook — Global ENSO Analysis Cell via ReliefWeb — https://reliefweb.int/report/world/global-update-september-2026-inter-agency-report-global-enso-analysis-cell-el-nino-status-humanitarian-outlook  ·  _read in full · captured 2026-10-03_\n- (primary) New NOAA El Niño-Southern Oscillation Index Supports Drought Early Warning — NOAA / Drought.gov — https://www.drought.gov/news/new-noaa-el-nino-southern-oscillation-index-supports-drought-early-warning-2026-03-11  ·  _read in full · captured 2026-10-03_\n- (primary) El Niño set to become very strong, raising risks of extreme weather into 2027 — World Meteorological Organization — https://wmo.int/news/media-centre/el-nino-set-become-very-strong-raising-risks-of-extreme-weather-2027  ·  _read in full · captured 2026-10-03_\n- (secondary) State of the climate: Rapidly developing El Niño raises chance of record-warm 2026 — Carbon Brief — https://www.carbonbrief.org/state-of-the-climate-rapidly-developing-el-nino-raises-chance-of-record-warm-2026  ·  _read in full · captured 2026-10-03_\n- (secondary) NOAA raises chance of historic-strength El Niño to 75% for October–December 2026 — The Watchers — https://watchers.news/2026/09/11/noaa-raises-chance-of-historic-strength-el-nino-to-75-for-october-december-2026  ·  _read in full · captured 2026-10-03_\n- (secondary) Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record — Carbon Brief — https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record  ·  _read in full · captured 2026-10-03_\n- (primary) ENSO: Recent Evolution, Current Status and Predictions - 10 September 2026 — NOAA CPC — https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf  ·  _full text not obtained — used its summary_\n- (primary) December 2023 El Niño update: adventure! — NOAA Climate.gov — https://www.climate.gov/news-features/blogs/enso/december-2023-el-nino-update-adventure  ·  _full text not obtained — used its summary_\n- (secondary) What's a 'super El Niño'? And other El Niño questions, answered — Yale Climate Connections — https://yaleclimateconnections.org/2026/05/whats-a-super-el-nino-and-other-el-nino-questions-answered  ·  _full text not obtained — used its summary_\n\n**Claims, and how far we tracked each down**\n- _[confirmed]_ Daily Niño 3.4 sea-surface temperature anomaly reached 3.11C as of 21 September 2026, surpassing the previous daily record of 3.08C set on 18 November 2015, calculated using the ONI convention (centered 30-year climatology, NOAA OISSTv2.1).  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ On RONI, daily values stood around 2.5C in mid-September 2026, about 0.7C below the all-time daily RONI record set in late December 1982-83, but were record-setting for that time of year.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ NOAA CPC September 2026 probabilities show 100% chance of El Niño from August-October 2026 through December-February 2027, then 97% February-April, 82% March-May, 43% April-June, with La Niña 0% through JFM and 2% by AMJ; very strong (>2C RONI) probabilities are 98% for October-December, 93% for November-January, 75% for December-February.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ An earlier 667-run analysis projected a median peak of 3.59C (ONI) and 3.1C (RONI) for July-December 2026, with 91% of runs (ONI) and 77% (RONI) exceeding the strongest event in the modern record (2.75C ONI in 2015-16, 2.69C RONI in 1982-83).  ·  read in full (as of 2026-10-03)\n- _[likely]_ Inter-agency and research estimates warn of large humanitarian risks: WFP via Global ENSO Analysis Cell estimates up to 50 million people could be affected over the next 6-9 months, and the University of Chicago Climate Impact Lab projected ~451,000 excess deaths by February 2027, with drought risk in the Greater Horn of Africa, Indonesia, Philippines, Australia and Central America and flood risk in coastal South America and southern Brazil.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ WMO forecasts an exceptionally high likelihood of nearly 100% that El Niño will persist through February 2027, strengthening to very strong intensity and peaking toward the end of 2026, with climate impacts continuing into 2027.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ NOAA's Oceanic Niño Index (ONI) uses a rolling centered 30-year average to remove long-term warming; the Relative ONI (RONI), adopted by NOAA CPC in February 2026, subtracts the tropical-mean (20N-20S) anomaly to better isolate ENSO variability.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ A very strong El Niño increases likelihood of major rainfall and temperature shifts but does not guarantee specific regional outcomes; WMO notes a positive Indian Ocean Dipole is expected to develop (~0.9C September-November) and the tropical Atlantic will remain warmer than normal, which may reinforce or alter typical El Niño teleconnections.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ The 2026 El Niño began in June 2026, reached the strong threshold (>1.5C) by June at 1.6C, exceeded 2C in early July, and has developed faster than any previous event on record.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ August 2026 monthly Niño 3.4 anomaly was around 2.45C, higher than the peak of every prior El Niño on record except 2015-16 (2.75C) and 1877-78 (~2.7C from sparse ship-data reconstruction).  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ El Niño strength is classed as weak at 0.5C, moderate above 1C, strong above 1.5C, and very strong/super above 2.0C Niño 3.4 anomaly.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ A 14-model ensemble (674 individual runs) projects a median peak monthly ONI anomaly around 4.1C later in 2026, with 80% of runs between 3.4C and 4.6C, every run above the 2015-16 record, and a margin over that record of ~1.3C larger than the gap between the strongest and fifth-strongest El Niños in 150 years.  ·  read in full (as of 2026-10-03)\n- _[likely]_ Carbon Brief estimated a 35% chance 2026 beats 2024 as warmest year (up from 19% in April), with a central estimate of ~1.51C above pre-industrial, and projects 2027 around 1.7C, which would comfortably set a new warmest-year record; El Niño's global temperature impact typically lags ocean warming by several months.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ WMO reported Niño 3.4 averaged +1.5C in May-July 2026 and +2.0C in July, with weekly values +2.2C to +2.6C in late July to mid-August, and subsurface temperatures more than 8C above average in July-early August.  ·  read in full (as of 2026-10-03)\n- _[likely]_ NOAA CPC's 10 September 2026 diagnostic reported August Niño 3.4 anomaly +1.8C, Niño 3 +2.5C, Niño 1+2 +3.4C, and subsurface anomalies exceeding +10C at depth.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ The first six months of 2026 were the third-warmest January-June on record (~1.4C above pre-industrial), with May and June the second-warmest ever behind 2024, and June 2026 was western Europe's hottest June on record.  ·  read in full (as of 2026-10-03)\n- _[likely]_ Since 1970, five recorded super El Niño events have been followed by a swift decline to neutral or La Niña conditions, a pattern cited as a precedent for a potential rapid collapse after the 2026-27 peak.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ The 2023-24 El Niño peaked around 2.0-2.1C on ONI (fifth-highest since 1950) but only ~1.5C on RONI (borderline strong), and the winters of 2024-25 and 2025-26 classified as ENSO-neutral on ONI would be classified as definitive La Niñas on RONI.  ·  read in full (as of 2026-10-03)\n- _[confirmed]_ El Niño typically occurs every 2-7 years, lasts 9-12 months, begins developing March-June and peaks November-February, with its largest influence on global temperatures felt in the year after development.  ·  read in full (as of 2026-10-03)\n\n**Where we hit a limit / what to double-check**\n- We did not obtain the full text of **What's a 'super El Niño'? And other El Niño questions, answered** (https://yaleclimateconnections.org/2026/05/whats-a-super-el-nino-and-other-el-nino-questions-answered); claims resting on it are from its summary — you may be able to reach it directly.\n- We did not obtain the full text of **ENSO: Recent Evolution, Current Status and Predictions - 10 September 2026** (https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf); claims resting on it are from its summary — you may be able to reach it directly.\n- We did not obtain the full text of **December 2023 El Niño update: adventure!** (https://www.climate.gov/news-features/blogs/enso/december-2023-el-nino-update-adventure); claims resting on it are from its summary — you may be able to reach it directly.","claims":[{"contradicted_by":[],"grade":"confirmed","id":"clm_1d329202e2","salience":"high","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"}],"text":"Daily Niño 3.4 sea-surface temperature anomaly reached 3.11C as of 21 September 2026, surpassing the previous daily record of 3.08C set on 18 November 2015, calculated using the ONI convention (centered 30-year climatology, NOAA OISSTv2.1)."},{"contradicted_by":[],"grade":"confirmed","id":"clm_dadf1bc8e6","salience":"high","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"}],"text":"August 2026 monthly Niño 3.4 anomaly was around 2.45C, higher than the peak of every prior El Niño on record except 2015-16 (2.75C) and 1877-78 (~2.7C from sparse ship-data reconstruction)."},{"contradicted_by":[],"grade":"confirmed","id":"clm_bdfd5aa44b","salience":"high","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"},{"published_at":"2026-07-24","publisher":"Carbon Brief","title":"State of the climate: Rapidly developing El Niño raises chance of record-warm 2026","url":"https://www.carbonbrief.org/state-of-the-climate-rapidly-developing-el-nino-raises-chance-of-record-warm-2026"},{"published_at":"2026-09-03","publisher":"World Meteorological Organization","title":"El Niño set to become very strong, raising risks of extreme weather into 2027","url":"https://wmo.int/news/media-centre/el-nino-set-become-very-strong-raising-risks-of-extreme-weather-2027"}],"text":"The 2026 El Niño began in June 2026, reached the strong threshold (>1.5C) by June at 1.6C, exceeded 2C in early July, and has developed faster than any previous event on record."},{"contradicted_by":[],"grade":"confirmed","id":"clm_e5d268e6e8","salience":"medium","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"},{"published_at":"2026-07-24","publisher":"Carbon Brief","title":"State of the climate: Rapidly developing El Niño raises chance of record-warm 2026","url":"https://www.carbonbrief.org/state-of-the-climate-rapidly-developing-el-nino-raises-chance-of-record-warm-2026"},{"published_at":"2023-12-13","publisher":"NOAA Climate.gov","title":"December 2023 El Niño update: adventure!","url":"https://www.climate.gov/news-features/blogs/enso/december-2023-el-nino-update-adventure"}],"text":"El Niño strength is classed as weak at 0.5C, moderate above 1C, strong above 1.5C, and very strong/super above 2.0C Niño 3.4 anomaly."},{"contradicted_by":[],"grade":"confirmed","id":"clm_b4e7add7fe","salience":"high","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"},{"published_at":"2026-03-11","publisher":"NOAA / Drought.gov","title":"New NOAA El Niño-Southern Oscillation Index Supports Drought Early Warning","url":"https://www.drought.gov/news/new-noaa-el-nino-southern-oscillation-index-supports-drought-early-warning-2026-03-11"},{"published_at":"2026-09-10","publisher":"NOAA Climate Prediction Center","title":"Official NOAA CPC ENSO Probabilities - September 2026","url":"https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/probabilities"}],"text":"NOAA's Oceanic Niño Index (ONI) uses a rolling centered 30-year average to remove long-term warming; the Relative ONI (RONI), adopted by NOAA CPC in February 2026, subtracts the tropical-mean (20N-20S) anomaly to better isolate ENSO variability."},{"contradicted_by":[],"grade":"confirmed","id":"clm_233d7a1830","salience":"high","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"}],"text":"On RONI, daily values stood around 2.5C in mid-September 2026, about 0.7C below the all-time daily RONI record set in late December 1982-83, but were record-setting for that time of year."},{"contradicted_by":[],"grade":"confirmed","id":"clm_eeeff7a6d5","salience":"high","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"}],"text":"A 14-model ensemble (674 individual runs) projects a median peak monthly ONI anomaly around 4.1C later in 2026, with 80% of runs between 3.4C and 4.6C, every run above the 2015-16 record, and a margin over that record of ~1.3C larger than the gap between the strongest and fifth-strongest El Niños in 150 years."},{"contradicted_by":[],"grade":"confirmed","id":"clm_5c0c201007","salience":"medium","sources":[{"published_at":"2026-07-24","publisher":"Carbon Brief","title":"State of the climate: Rapidly developing El Niño raises chance of record-warm 2026","url":"https://www.carbonbrief.org/state-of-the-climate-rapidly-developing-el-nino-raises-chance-of-record-warm-2026"}],"text":"An earlier 667-run analysis projected a median peak of 3.59C (ONI) and 3.1C (RONI) for July-December 2026, with 91% of runs (ONI) and 77% (RONI) exceeding the strongest event in the modern record (2.75C ONI in 2015-16, 2.69C RONI in 1982-83)."},{"contradicted_by":[],"grade":"confirmed","id":"clm_058f2142fa","salience":"high","sources":[{"published_at":"2026-09-03","publisher":"World Meteorological Organization","title":"El Niño set to become very strong, raising risks of extreme weather into 2027","url":"https://wmo.int/news/media-centre/el-nino-set-become-very-strong-raising-risks-of-extreme-weather-2027"}],"text":"WMO reported Niño 3.4 averaged +1.5C in May-July 2026 and +2.0C in July, with weekly values +2.2C to +2.6C in late July to mid-August, and subsurface temperatures more than 8C above average in July-early August."},{"contradicted_by":[],"grade":"likely","id":"clm_16a22e2d19","salience":"medium","sources":[{"published_at":"2026-09-11","publisher":"The Watchers","title":"NOAA raises chance of historic-strength El Niño to 75% for October–December 2026","url":"https://watchers.news/2026/09/11/noaa-raises-chance-of-historic-strength-el-nino-to-75-for-october-december-2026"}],"text":"NOAA CPC's 10 September 2026 diagnostic reported August Niño 3.4 anomaly +1.8C, Niño 3 +2.5C, Niño 1+2 +3.4C, and subsurface anomalies exceeding +10C at depth."},{"contradicted_by":[],"grade":"confirmed","id":"clm_aca23d1a45","salience":"high","sources":[{"published_at":"2026-09-03","publisher":"World Meteorological Organization","title":"El Niño set to become very strong, raising risks of extreme weather into 2027","url":"https://wmo.int/news/media-centre/el-nino-set-become-very-strong-raising-risks-of-extreme-weather-2027"},{"published_at":"2026-09-17","publisher":"Global ENSO Analysis Cell via ReliefWeb","title":"Global Update September 2026: El Niño Status & Humanitarian Outlook","url":"https://reliefweb.int/report/world/global-update-september-2026-inter-agency-report-global-enso-analysis-cell-el-nino-status-humanitarian-outlook"}],"text":"WMO forecasts an exceptionally high likelihood of nearly 100% that El Niño will persist through February 2027, strengthening to very strong intensity and peaking toward the end of 2026, with climate impacts continuing into 2027."},{"contradicted_by":[],"grade":"confirmed","id":"clm_5b314f02bd","salience":"high","sources":[{"published_at":"2026-09-10","publisher":"NOAA Climate Prediction Center","title":"Official NOAA CPC ENSO Probabilities - September 2026","url":"https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/probabilities"},{"published_at":"2026-09-11","publisher":"The Watchers","title":"NOAA raises chance of historic-strength El Niño to 75% for October–December 2026","url":"https://watchers.news/2026/09/11/noaa-raises-chance-of-historic-strength-el-nino-to-75-for-october-december-2026"},{"published_at":"2026-09-10","publisher":"NOAA CPC","title":"ENSO: Recent Evolution, Current Status and Predictions - 10 September 2026","url":"https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf"}],"text":"NOAA CPC September 2026 probabilities show 100% chance of El Niño from August-October 2026 through December-February 2027, then 97% February-April, 82% March-May, 43% April-June, with La Niña 0% through JFM and 2% by AMJ; very strong (>2C RONI) probabilities are 98% for October-December, 93% for November-January, 75% for December-February."},{"contradicted_by":[],"grade":"confirmed","id":"clm_23686f2339","salience":"medium","sources":[{"published_at":"2026-07-24","publisher":"Carbon Brief","title":"State of the climate: Rapidly developing El Niño raises chance of record-warm 2026","url":"https://www.carbonbrief.org/state-of-the-climate-rapidly-developing-el-nino-raises-chance-of-record-warm-2026"}],"text":"The first six months of 2026 were the third-warmest January-June on record (~1.4C above pre-industrial), with May and June the second-warmest ever behind 2024, and June 2026 was western Europe's hottest June on record."},{"contradicted_by":[],"grade":"likely","id":"clm_f96921a968","salience":"high","sources":[{"published_at":"2026-09-21","publisher":"Carbon Brief","title":"Analysis: ‘Super El Niño’ breaks ‘remarkable’ all-time record","url":"https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record"},{"published_at":"2026-07-24","publisher":"Carbon Brief","title":"State of the climate: Rapidly developing El Niño raises chance of record-warm 2026","url":"https://www.carbonbrief.org/state-of-the-climate-rapidly-developing-el-nino-raises-chance-of-record-warm-2026"}],"text":"Carbon Brief estimated a 35% chance 2026 beats 2024 as warmest year (up from 19% in April), with a central estimate of ~1.51C above pre-industrial, and projects 2027 around 1.7C, which would comfortably set a new warmest-year record; El Niño's global temperature impact typically lags ocean warming by several months."},{"contradicted_by":[],"grade":"confirmed","id":"clm_bac9428457","salience":"medium","sources":[{"published_at":"2026-09-03","publisher":"World Meteorological Organization","title":"El Niño set to become very strong, raising risks of extreme weather into 2027","url":"https://wmo.int/news/media-centre/el-nino-set-become-very-strong-raising-risks-of-extreme-weather-2027"}],"text":"A very strong El Niño increases likelihood of major rainfall and temperature shifts but does not guarantee specific regional outcomes; WMO notes a positive Indian Ocean Dipole is expected to develop (~0.9C September-November) and the tropical Atlantic will remain warmer than normal, which may reinforce or alter typical El Niño teleconnections."},{"contradicted_by":[],"grade":"likely","id":"clm_92b3ed882c","salience":"medium","sources":[{"published_at":"2026-09-17","publisher":"Global ENSO Analysis Cell via ReliefWeb","title":"Global Update September 2026: El Niño Status & Humanitarian Outlook","url":"https://reliefweb.int/report/world/global-update-september-2026-inter-agency-report-global-enso-analysis-cell-el-nino-status-humanitarian-outlook"}],"text":"Inter-agency and research estimates warn of large humanitarian risks: WFP via Global ENSO Analysis Cell estimates up to 50 million people could be affected over the next 6-9 months, and the University of Chicago Climate Impact Lab projected ~451,000 excess deaths by February 2027, with drought risk in the Greater Horn of Africa, Indonesia, Philippines, Australia and Central America and flood risk in coastal South America and southern Brazil."},{"contradicted_by":[],"grade":"likely","id":"clm_66c9974a9a","salience":"medium","sources":[{"published_at":"2026-09-11","publisher":"The Watchers","title":"NOAA raises chance of historic-strength El Niño to 75% for October–December 2026","url":"https://watchers.news/2026/09/11/noaa-raises-chance-of-historic-strength-el-nino-to-75-for-october-december-2026"}],"text":"Since 1970, five recorded super El Niño events have been followed by a swift decline to neutral or La Niña conditions, a pattern cited as a precedent for a potential rapid collapse after the 2026-27 peak."},{"contradicted_by":[],"grade":"confirmed","id":"clm_a06c334cb1","salience":"low","sources":[{"published_at":"2026-09-03","publisher":"World Meteorological Organization","title":"El Niño set to become very strong, raising risks of extreme weather into 2027","url":"https://wmo.int/news/media-centre/el-nino-set-become-very-strong-raising-risks-of-extreme-weather-2027"}],"text":"El Niño typically occurs every 2-7 years, lasts 9-12 months, begins developing March-June and peaks November-February, with its largest influence on global temperatures felt in the year after development."},{"contradicted_by":[],"grade":"confirmed","id":"clm_7f1f26a467","salience":"low","sources":[{"published_at":"2026-03-11","publisher":"NOAA / Drought.gov","title":"New NOAA El Niño-Southern Oscillation Index Supports Drought Early Warning","url":"https://www.drought.gov/news/new-noaa-el-nino-southern-oscillation-index-supports-drought-early-warning-2026-03-11"},{"published_at":"2026-05-15","publisher":"Yale Climate Connections","title":"What's a 'super El Niño'? And other El Niño questions, answered","url":"https://yaleclimateconnections.org/2026/05/whats-a-super-el-nino-and-other-el-nino-questions-answered"}],"text":"The 2023-24 El Niño peaked around 2.0-2.1C on ONI (fifth-highest since 1950) but only ~1.5C on RONI (borderline strong), and the winters of 2024-25 and 2025-26 classified as ENSO-neutral on ONI would be classified as definitive La Niñas on RONI."}],"sources":["https://www.carbonbrief.org/analysis-super-el-nino-reaches-remarkable-all-time-record","https://www.carbonbrief.org/state-of-the-climate-rapidly-developing-el-nino-raises-chance-of-record-warm-2026","https://wmo.int/news/media-centre/el-nino-set-become-very-strong-raising-risks-of-extreme-weather-2027","https://www.climate.gov/news-features/blogs/enso/december-2023-el-nino-update-adventure","https://www.drought.gov/news/new-noaa-el-nino-southern-oscillation-index-supports-drought-early-warning-2026-03-11","https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/probabilities","https://watchers.news/2026/09/11/noaa-raises-chance-of-historic-strength-el-nino-to-75-for-october-december-2026","https://reliefweb.int/report/world/global-update-september-2026-inter-agency-report-global-enso-analysis-cell-el-nino-status-humanitarian-outlook","https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf","https://yaleclimateconnections.org/2026/05/whats-a-super-el-nino-and-other-el-nino-questions-answered"],"corrections":[],"how_to_cite":"Cite the article URL and the claim id. Grades are Ohmega's assessment of each claim as of the date shown, not a guarantee. Source texts belong to their publishers.","cite_as":"https://ohmega.monster/articles/el-ni-o-the-pacific-warming-that-shifts-world-weather-breaks-3e7f96","api_url":"https://ohmega.monster/api/v1/articles/el-ni-o-the-pacific-warming-that-shifts-world-weather-breaks-3e7f96","data_url":"https://ohmega.monster/data/articles/el-ni-o-the-pacific-warming-that-shifts-world-weather-breaks-3e7f96.json"},"meta":{"as_of":"2026-09-23","source":"ohmega.article/1","version":"v1","cite_as":"https://ohmega.monster/articles/el-ni-o-the-pacific-warming-that-shifts-world-weather-breaks-3e7f96","license":"Ohmega claims, summaries, grades, Pulses and forecasts may be quoted with a link to cite_as. Source texts belong to their publishers; follow the source URLs. No warranty: readings are our assessment as of as_of, not guarantees.","verification":"publishable","note":"claims[] (when present) carry grade: confirmed, likely, contested, unconfirmed/speculative (a lead, not established), opinion (attributed). Grades are our assessment as of as_of."}}