Series · Understanding El Niño
El Niño 2026: what makes it different and what official reports say
An intense event, a new way of measuring it, and forecasts that still need to be verified. We read the reports without turning a probability into a certainty.
The report date matters
This article was documented on 6 November 2026. using the October 8 CPC monthly bulletin and the WMO declaration of October 21. The CPC bulletin itself marks its next discussion for 12 November. We are reading a dated photograph of available knowledge, not a live update. [1]
When you return to this text, check the original links as well. A new forecast may change the figures; that does not make the previous document incorrect, but it does change what information should be used for a current decision.
An episode with high intensity signals
In his discussion of 8 OctoberThe CPC described a strengthening El Niño. He estimated a probability of 83% by October–December 2026 to reach a historic event, using as a criterion a RONI quarterly of +2.5 °C or more. That percentage refers to that intensity criterion and to that period, not to a probability of flooding in Baja California Sur. [1]
The difference is essential: the report combines observations of the system and estimates of its evolution. To present all the figures as if they had already occurred would erase that distinction.
The WMO projection is another piece, not the same number
WMO reported that 21 October a projection of surface temperatures of the tropical Pacific up to 3.8 °C above average for November 2026 to January 2027. He expressed it as a planned scenario, not as the final result of the entire episode. [2]
We should not simply compare this anomaly with the previous quarterly RONI. They are different documents, periods and measures. A regional temperature forecast is also not equivalent to the temperature a traveler will find in La Ventana.
In 2026 it also changed the measuring lens
The CPC announced in February its transition to RONI: a comparison of the ENSO region with the tropics as a whole. This decision seeks to improve monitoring when background warming complicates the use of a traditional reference. [3]
When comparing “this year” with another, the same index, period and method must be maintained. A headline with a larger figure may be mixing metrics; historical comparison requires more than putting two numbers side by side.
Different does not mean predictable in every detail
USGS recalls that there are few very intense episodes to use as analogies and that past events were not identical. WMO also clarifies that its seasonal prospects are not predictions of individual events. [4][2]
We can say that the documents consulted describe and anticipate an exceptionally intense episode. We cannot turn that into an assertion that there will be a particular species, a particular storm, or an exact condition during an expedition. That jump would require additional local evidence.
Scientific and official references
- NOAA, Climate Prediction Center. (October 8, 2026). ENSO Diagnostic Discussion. Referral: November 6, 2026.
- World Meteorological Organization; Celeste Saulo (October 21, 2026). El Niño and humanitarian action. Referral: November 6, 2026.
- NOAA, Climate Prediction Center. (February 2026). CPC adoptions Relative Oceanic Niño Index (RONI). Referral: November 6, 2026.
- USGS, Climate Adaptation Science Centers. (2026). 2026 El Niño: What Does It Mean for Resource Managers?. Referral: November 6, 2026.
The numbered quotations link to the document that supports each statement. Forecasts are presented with their date and period; this article is not automatically updated.
