Is This the Strongest El Niño Ever Measured?

In the last week of September 2026, the Pacific off the coast of Peru was 5.3 °C warmer than normal, the highest in NOAA's weekly records, which go back to 1981. So is this the strongest El Niño ever measured? NOAA keeps two rulers. On the traditional one, the weekly records have already fallen. On the official relative index, not yet: in September, NOAA gave it a 75% chance of passing every El Niño since 1950 by December.

We built the maps from NOAA's daily satellite data and measured the numbers ourselves: the part of the Pacific at least 3 °C above normal (9.98 million km², the size of Canada), the Niño 3.4 box (6.15 million km² on the WGS84 ellipsoid) and the temperature gap across the equator. Then we follow the rain, from the desert coast of Peru to India's monsoon and the winter in the United States. Figures are as of early October 2026.

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Chapters
00:00 Is this the strongest El Niño ever measured?
01:23 The box
02:43 Two rulers
04:09 A normal year
05:34 When the wind slows
06:35 Peru and Ecuador
07:31 Indonesia, India and Australia
08:39 Africa
09:14 The Americas
10:10 What comes next

Sources
- NOAA CPC, weekly Niño indices, traditional and relative: https://www.cpc.ncep.noaa.gov/data/indices/wksst9120.for and https://www.cpc.ncep.noaa.gov/data/indices/rel_wksst9120.txt
- NOAA CPC, monthly relative indices and RONI: https://www.cpc.ncep.noaa.gov/data/indices/rel_mthsst9120.txt and https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt
- NOAA CPC, ENSO Diagnostic Discussion (10 Sep 2026): https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_disc_sep2026/ensodisc.shtml
- NOAA CPC, ENSO update (5 Oct 2026): https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
- NOAA/NCEI, OISST v2.1 daily sea surface temperature: https://www.ncei.noaa.gov/products/optimum-interpolation-sst
- NOAA PMEL, What is El Niño?: https://www.pmel.noaa.gov/elnino/what-is-el-nino
- NOAA Ocean Service, What are El Niño and La Niña? (origin of the name): https://oceanservice.noaa.gov/facts/ninonina.html
- ENFEN Peru, Comunicado Oficial N° 17-2026 (28 Sep 2026): https://enfen.imarpe.gob.pe/download/comunicado-oficial-enfen-n-17-2026/
- IGP, Woodman & Takahashi, Boletín Técnico vol. 1 n° 6 (2014), Piura rainfall: http://sigrid.cenepred.gob.pe/docs/PARA%20PUBLICAR/IGP/Boletin_Tecnico_PPR_El_Nino_IGP_201406.pdf
- CN-ERFEN Ecuador, Informe 010-2026 (1 Oct 2026): https://alertasecuador.gob.ec/el_nino/wp-content/uploads/2026/10/erfen_20261001.pdf
- PRODUCE Peru, first anchovy season (20 Aug 2026): https://www.gob.pe/institucion/produce/noticias/1432630-produce-concluye-la-primera-temporada-de-anchoveta-en-la-zona-norte-centro
- BMKG Indonesia (22 Sep 2026): https://www.bmkg.go.id/siaran-pers/bmkg-el-nino-sangat-kuat-sedang-terjadi-musim-hujan-2026-2027-diprediksi-datang-lebih-lambat
- IMD India, 2026 southwest monsoon (30 Sep 2026): https://internal.imd.gov.in/press_release/20260930_pr_5358.pdf
- Bureau of Meteorology, climate driver update (29 Sep 2026): https://www.bom.gov.au/climate/enso/
- ICPAC, GHACOF 74 (18 Aug 2026): https://www.icpac.net/news/the-greater-horn-of-africa-is-expected-to-experience-a-wetter-than-normal-october-december-ond-2026-season-as-el-ni%C3%B1o-strengthens/
- SADC, SARCOF-33 (27 Aug 2026): https://www.sadc.int/latest-news/sadc-outlook-favours-drier-conditions-across-much-southern-africa-during-202627-rainy
- WFP, southern Africa drought (15 May 2024): https://www.wfp.org/stories/southern-africa-el-nino-drought-leaves-trail-scorched-harvests-and-hunger
- NOAA CPC, 90-day outlook (17 Sep 2026): https://www.cpc.ncep.noaa.gov/products/predictions/90day/fxus05.html
- INMET Brazil, Painel El Niño (30 Sep 2026): https://portal.inmet.gov.br/noticias/el-ni%C3%B1o
- SGB Brazil, Rio Negro at Manaus, technical note (2025)
- NOAA NCEI, Climate at a Glance, global annual temperature: https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series
- Berkeley Earth, August 2026 temperature update (24 Sep 2026): https://berkeleyearth.org/august-2026-temperature-update/

Maps: NASA Earth Observatory (Blue Marble Next Generation, Reto Stöckli), GMRT, Ryan et al. (2009) (CC BY 4.0), Natural Earth (public domain). Sea surface temperature: NOAA/NCEI OISST v2.1. Illustrations: AI-generated. Music: Epidemic Sound. Narration: AI voice (Epidemic Sound).
Photos: TAO buoy, Lt. Cmdr. Matthew Wingate, NOAA Corps, NOAA Photo Library (CC BY 2.0). Coast of Peru, ISS059-E-39541, image courtesy of the Earth Science and Remote Sensing Unit, NASA Johnson Space Center (eol.jsc.nasa.gov). Rio Negro at Manaus, 20 Jul and 18 Oct 2024: contains modified Copernicus Sentinel data (2024).