New Relative Niño index introduces more robust way to measure El Niño strength

Phys · Jun 08, 2026 · 516 words · By ECMWF

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What to know about New Relative Niño index introduces more robust way to measure El Niño strength

The European Centre for Medium-Range Weather Forecasts (ECMWF) has released the Relative Niño index, a new method for measuring El Niño strength that accounts for rising global background temperatures. This index compares central Pacific warming with wider tropical temperatures to provide a more accurate assessment of climate events in a warming world.

Propaganda risk 10%

Claims checked 8

Techniques found 0

Topics 0

Coverage spectrum

Coverage gap: Low Left coverage

Left0%

Center80%

Right20%

5 sources compared across this story cluster. This is an eFinder estimate from indexed source coverage, not an editorial rating.

What happened

New Relative Niño index introduces more robust way to measure El Niño strength Stephanie Baum Scientific Editor Robert Egan Associate Editor A new El Niño index that provides a more climate-robust measure of the strength of El Niño signals has been released…

Why it matters

With the World Meteorological Organization's recent update indicating an 80% likelihood of an El Niño event during June–August 2026 and a 90% probability of this continuing until at least November, it is more important than ever to have accurate, reliable…

Common ground

While the traditional Niño indices previously relied on comparing current sea-surface temperatures with a fixed historical baseline, the new measure, known as the Relative Niño index, compares warming in the central Pacific with temperatures across the wider…

Perspective signals

No major persuasion pattern has been attached yet, so the source, headline, and evidence should carry most of the weight for readers.

Follow-up questions

What concrete event or decision sits underneath the headline: New Relative Niño index introduces more robust way to measure El Niño strength?
What evidence would most clearly confirm or weaken the claim that the new measure, known as the Relative Niño index, compares warming in the central Pacific with temperatures across the wider tropics?
What should readers watch for in the next update to know whether the story is changing?

open_in_new Read the original article: https://phys.org/news/2026-06-nio-index-robust-el-strength.html

analyticsAnalysis

10%

Propaganda Score

confidence: 95%

Low risk. This article shows minimal use of propaganda techniques.

fact_checkClaims Checked

eFinder analyzed this article and checked 8 claims against available evidence, cross-references, web search, and Wikipedia. Here is what the fact-checking layer found.

check_circle Corroborated 6

info Single Source 1

verified Verified By Reference 1

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Claim 1: “the new measure, known as the Relative Niño index, compares warming in the central Pacific with temperatures across the wider tropics.”

CORROBORATED

Web search results explicitly describe the Relative Niño index (or Relative Oceanic Nino Index - RONI) as measuring Pacific temperatures relative to the wider tropics/overall temperature.

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wikipedia NEUTRAL — The Atlantic Equatorial Mode or Atlantic Niño is a quasiperiodic interannual climate pattern of the equatorial Atlantic Ocean. It is the dominant mode of year-to-year variability that results in alt…
https://en.wikipedia.org/wiki/Atlantic_Equatorial_mode

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wikipedia NEUTRAL — El Niño–Southern Oscillation (ENSO) is a global climate phenomenon that emerges from variation in winds and sea surface temperatures over the tropical Pacific Ocean. Those variations have an irregular…
https://en.wikipedia.org/wiki/El_Niño–Southern_Oscillation

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wikipedia NEUTRAL — The Señor Santo Niño de Cebú (lit. 'Lord Holy Child of Cebu'), or simply the Santo Niño, is a Catholic title of the Child Jesus associated with a religious image widely venerated as miraculous by Fili…
https://en.wikipedia.org/wiki/Santo_Niño_de_Cebú

+ 3 more evidence sources

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Claim 2: “the World Meteorological Organization's recent update indicating an 80% likelihood of an El Niño event during June–August 2026 and a 90% probability of this continuing until at least November”

CORROBORATED

Multiple independent sources, including a WMO update and LinkedIn professional reports, confirm the 80% likelihood for June-August 2026 and the 90% probability of persistence until November.

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wikipedia NEUTRAL — The 2014–2016 El Niño was the second-strongest El Niño event on record, with unusually warm waters developing between the coast of South America and the International Date Line. These unusually warm w…
https://en.wikipedia.org/wiki/2014–2016_El_Niño_event

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wikipedia NEUTRAL — The 2023–2024 El Niño was regarded as the fifth-most powerful El Niño–Southern Oscillation event in recorded history, resulting in widespread droughts, flooding and other natural disasters across the …
https://en.wikipedia.org/wiki/2023–2024_El_Niño_event

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wikipedia NEUTRAL — The World Meteorological Organization (WMO) is a specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophys…
https://en.wikipedia.org/wiki/World_Meteorological_Organizat…

+ 3 more evidence sources

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Claim 3: “A new El Niño index that provides a more climate-robust measure of the strength of El Niño signals has been released by the European Centre for Medium-Range Weather Forecasts (ECMWF).”

CORROBORATED

Multiple independent web search results confirm that the ECMWF released a new, more climate-robust El Niño index.

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wikipedia NEUTRAL — The European Centre for Medium-Range Weather Forecasts (ECMWF) is an independent intergovernmental organisation supported by most of the nations of Europe. It is based at three sites: Shinfield Park, …
https://en.wikipedia.org/wiki/European_Centre_for_Medium-Ran…

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wikipedia NEUTRAL — Foreca Ltd () is a private Finnish weather forecasting company. It is the largest of its kind in the Nordic countries and is headquartered in Espoo, Finland. Foreca provides weather services for inter…
https://en.wikipedia.org/wiki/Foreca

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wikipedia NEUTRAL — The Weather Prediction Center (WPC), located in College Park, Maryland, is one of nine service centers under the umbrella of the National Centers for Environmental Prediction (NCEP), a part of the Nat…
https://en.wikipedia.org/wiki/Weather_Prediction_Center

+ 3 more evidence sources

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Claim 4: “Providing the index in this new form, as recently recommended by WMO”

CORROBORATED

The ECMWF source explicitly states that the Relative Niño indices were 'developed with partners and supported by WMO'.

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web search NEUTRAL — WMO issues quarterly El Niño/La Niña Updates prepared through a collaborative effort between WMO and the International Research Institute for Climate and ...
https://wmo.int/themes/el-nino-la-nina-phenomena

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web search NEUTRAL — Jun 10, 2026 ... ECMWF introduces Relative Niño indices, developed with partners and supported by WMO, to better assess El Niño strength in a warming climate ...
https://www.ecmwf.int/en/about/media-centre/science-blog/202…

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web search NEUTRAL — 2 days ago ... In a warming climate, scientists are also looking at the Relative Oceanic Niño Index (RONI). It measures how warm or cool the equatorial Pacific ...
https://www.facebook.com/WorldMeteorologicalOrganization/pos…

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Claim 5: “The Relative Niño index is provided on approximately the same scale as the traditional Niño index”

SINGLE SOURCE

While the existence of the index is corroborated, the specific detail that it is on 'approximately the same scale' as the traditional index is not explicitly confirmed across multiple independent sources in the provided evidence.

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web search NEUTRAL — ECMWF introduces Relative Niño indices, developed with partners and supported by WMO, to better assess El Niño strength in a warming climate as forecasts suggest an unusually strong El Niño event in 2…
https://www.ecmwf.int/en/about/media-centre/science-blog/202…

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web search NEUTRAL — Relative Niño index introduces more robust way to measure El Niño strength.An El Niño index that provides a more climate-robust measure of the strength of El Niño signals has been released by the Euro…
https://www.preventionweb.net/news/relative-nino-index-intro…

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web search NEUTRAL — About relative Niño indices. Until August 2025 the Bureau used the traditional Niño index to track sea surface temperatures in the Pacific Ocean. As the Pacific Ocean has gradually warmed, so have the…
https://www.miragenews.com/relative-nino-new-el-nino-measure…

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Claim 6: “traditional Niño indices previously relied on comparing current sea-surface temperatures with a fixed historical baseline”

CORROBORATED

Two independent sources (Watts Up With That? and a source on ENSO indices) confirm that traditional indices rely on a fixed historical baseline.

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web search NEUTRAL — The ONI is founded on an assumption: sea surface temperature (SST) anomalies in the Niño-3.4 region, measured relative to a historical baseline, adequately represent the state of ENSO.
https://wmo.int/sites/default/files/2026-05/Understanding+EN…

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web search NEUTRAL — While the traditional Niño indices previously relied upon, compare current sea-surface temperatures with a fixed historical baseline, the new measure, known as the Relative Niño index, compares warmin…
https://wattsupwiththat.com/2026/06/11/proposed-new-el-nino-…

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web search NEUTRAL — Historically Speaking. El Niño and La Niña events tend to develop during the period Apr-Jun and they. Tend to reach their maximum strength during October - February. Typically persist for 9-12 months,…
https://iri.columbia.edu/our-expertise/climate/forecasts/ens…

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Claim 7: “The new Relative El Niño indices compare the Niño 3.4 and other regions with the overall temperature of the tropics at the same time”

CORROBORATED

The ECMWF source explicitly states that these indices compare the Niño 3.4 region with the rest of the tropics at the same time.

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wikipedia NEUTRAL — Portrait of Fernando Niño de Guevara is a 1600 painting of cardinal Fernando Niño de Guevara by El Greco, now in the Metropolitan Museum of Art in New York. In the article, "Three Paintings by El Grec…
https://en.wikipedia.org/wiki/Portrait_of_Fernando_Niño_de_G…

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+ 3 more evidence sources

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Claim 8: “At the core are the Niño sea-surface temperature indices—Niño 3.4, Niño 3, Niño 4, and Niño 1+2—which track sea-surface temperature anomalies in different parts of the tropical Pacific.”

VERIFIED BY REFERENCE

Wikipedia and NOAA confirm that El Niño is tracked via sea-surface temperature anomalies in the tropical Pacific, and the specific regions (Niño 3.4, 3, 4, 1+2) are standard meteorological indices for this purpose.

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wikipedia NEUTRAL — Super El Niño events, also called very strong El Niño events, are climatic phenomena resulting from the average sea surface temperatures in parts of the Pacific Ocean rising by 2° Celsius or more, aff…
https://en.wikipedia.org/wiki/Super_El_Niño_events

+ 3 more evidence sources

info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.