Each dot on this scatterplot shows the subsurface temperature anomaly (difference from the long-term average) in the central tropical Pacific each September (horizontal axis) since 1979 versus the oceanic ENSO conditions the following November–January (vertical axis). The vertical red line show the September 2023 subsurface temperature anomaly. The amount of warmer-than-average water under the surface in September has a strong relationship with the oceanic ENSO conditions later in the year. Previous very strong El Niño events, 1982–83,1997–98, and 2015–16, had more subsurface warm water than 2023. Data from CPC, image by Climate.gov.