{"id":449935,"date":"2026-06-12T08:29:54","date_gmt":"2026-06-12T15:29:54","guid":{"rendered":"https:\/\/climatescience.press\/?p=449935"},"modified":"2026-06-12T08:29:56","modified_gmt":"2026-06-12T15:29:56","slug":"proposed-new-el-nino-index-to-measure-el-nino-strength","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=449935","title":{"rendered":"Proposed New El Ni\u00f1o Index to Measure El Ni\u00f1o strength"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

From Watts Up With That?<\/a><\/p>\n\n\n\n

By Anthony Watts<\/a><\/p>\n\n\n\n

From the ECMWF and the robusted department of climate hubris, comes this announcement.<\/em> -Anthony<\/p>\n\n\n\n

A new El Ni\u00f1o index that brings a more climate-robust measure of the strength of El Ni\u00f1o signals has been released by the European Centre for Medium-Range Weather Forecasts (ECMWF). With the World Meteorological Organisation\u2019s recent update<\/a> indicating an 80% likelihood of an El Ni\u00f1o event during June-August 2026 and a 90 percent probability of this continuing until at least November, it is more important than ever to have accurate data to rely on.<\/p>\n\n\n\n

While the traditional Ni\u00f1o indices previously relied upon, compare current sea-surface temperatures with a fixed historical baseline, the new measure, known as the Relative Ni\u00f1o index, compares warming in the central Pacific with temperatures across the wider tropics. This can give a clearer picture of how unusual the conditions really are in today\u2019s warming climate:<\/p>\n\n\n\n

\u201cAs the climate warms, interpreting anomalies becomes more challengin<\/em>g\u201d, said Dr Tim Stockdale, Principal Scientist at ECMWF.<\/p>\n\n\n\n

\u201cRising background temperatures can make recent El Ni\u00f1o events appear stronger than they are, and La Ni\u00f1a events seem weaker. The new Relative El Ni\u00f1o indices compare the Ni\u00f1o 3.4 and other regions with the overall temperature of the tropics at the same time, offering a perspective that is less sensitive to long-term warming. This will provide an additional tool for describing the likely strength of an upcoming El Ni\u00f1o event. Even with this adjustment, the strength of the forecasts suggests that El Ni\u00f1o may be unusually strong later in the year<\/em>\u201d.<\/p>\n\n\n\n

The new index is also more suited for monitoring and comparing events over time. It is less sensitive to picking up the background signal of global warming trends, meaning El Ni\u00f1o can be described more accurately and with greater separation from climate change.<\/p>\n\n\n\n

It joins a range of El Ni\u00f1o indices and products; each designed for a slightly different scientific purpose. At the core are the Ni\u00f1o sea-surface temperature indices \u2014 Ni\u00f1o 3.4, Ni\u00f1o 3, Ni\u00f1o 4, and Ni\u00f1o 1+2, which track sea-surface temperature anomalies in different parts of the tropical Pacific. These are widely used to monitor where warming or cooling is concentrated and to assess the evolution of El Ni\u00f1o and La Ni\u00f1a events.<\/p>\n\n\n\n

The Relative Ni\u00f1o index is provided on approximately the same scale as the traditional Ni\u00f1o index meaning forecasters and other users can adopt it without having to relearn thresholds or interpretation.<\/p>\n\n\n\n

Florian Pappenberger, Director-General of ECMWF, said:<\/p>\n\n\n\n

\u201cProviding the index in this new form, as recently recommended by WMO, should mean it can be adopted almost immediately. Producing it has been a huge collective endeavour from ECMWF and its partners. We are grateful to the WMO for the support they have shown throughout this process. It has been a long time in the making, but its availability now has become more crucial than ever with indicators pointing towards the potential for an El Ni\u00f1o event of at least moderate strength but possibly reaching strong intensity. We could be looking at an event as significant as any we have seen in the past 50 years<\/em>\u201d.<\/p>\n\n\n\n

[UPDATE]<\/strong> Now that you know about the new whiz-bang Relative Oceanic Ni\u00f1o Index, I\u2019m sure Anthony won\u2019t mind if I show you just how big an improvement it is \u2026<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Be still, my beating heart \u2026 methinks someone at ECMWF has too much time on their hands.<\/p>\n\n\n\n

w.<\/p>\n","protected":false},"excerpt":{"rendered":"

Rising background temperatures have been making recent El Ni\u00f1o events appear stronger than they really are. <\/p>\n

The European Centre for Medium-Range Weather Forecasts has a new fix for that. <\/p>\n","protected":false},"author":121246920,"featured_media":449943,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[],"class_list":["post-449935","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","fallback-thumbnail"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/06\/0-ChatGPT-Proposed-New-El-Nino-Index-to-Measure-El-Nino-strength.png?fit=1536%2C1024&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-1T31","jetpack-related-posts":[{"id":445799,"url":"https:\/\/climatescience.press\/?p=445799","url_meta":{"origin":449935,"position":0},"title":"About That \u201cSuper El Ni\u00f1o\u201d","author":"uwe.roland.gross","date":"05\/22\/2026","format":false,"excerpt":"On Thursday, May 14, the NOAA Climate Prediction Center issued its monthly ENSO Diagnostic Discussion. 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