Pacific Ocean heat anomaly sets new September record, signaling powerful El Niño
Sea surface temperatures in a key equatorial Pacific region have reached 3.05 degrees Celsius above normal, the highest anomaly for late September in over a century of record-keeping. Climate scientists describe the event as potentially the strongest El Niño of our lifetimes, with global weather impacts expected. The record underscores the combined effects of natural climate variability and background warming from climate change.
The equatorial Pacific monitoring region has now surpassed the previous late-September benchmark set in 2015, when temperatures ran 3.02 degrees Celsius above normal. This year's reading of 3.05 degrees Celsius marks the warmest such anomaly since systematic tracking began more than a century ago. Climate specialist Jeff Berardelli highlighted the figure in public posts, while University of Arizona researcher Kim Wood characterized conditions as "unparalleled" for this point in the seasonal cycle.
Scientists note that even when accounting for background warming from climate change, the current anomaly remains exceptional for late September. Daniel Swain of UCANR anticipates this may become the strongest El Niño experienced in living memory. Historically, El Niño events elevate global average temperatures, placing both this year and next at heightened risk of ranking among the hottest on record.
This record-breaking anomaly could amplify weather disruptions worldwide, affecting agriculture, water supplies, and disaster preparedness across multiple continents. Southern U.S. regions may face increased flooding while Pacific Northwest communities could experience drought conditions. The compounding of natural El Niño variability with climate change may strain infrastructure and emergency response systems. Global temperature increases associated with this event could also intensify heat-related health risks, particularly for vulnerable populations lacking adequate cooling or healthcare access.