Record High Sea Surface Temperatures in 2023

Abstract

NOAA Daily Optimum Interpolation Sea Surface Temperature (DOISST) and other similar sea surface temperature (SST) products indicate that the globally averaged SST set a new daily record in March 2023. The record-high SST in March was immediately broken in April, and new daily records were set again in July and August 2023. The SST anomaly (SSTA) persisted at a record high from mid-March to the remainder of 2023. Our analysis indicates that the record-high SSTs, and associated marine heatwaves (MHWs) and even super-MHWs, are attributed to three factors: (a) a long-term warming trend, (b) a shift to the warm phase of the multi-decadal Pacific-Atlantic-Arctic (PAA) mode, and (c) the transition from the triple-dip succession of La Niña events to the 2023–24 El Niño event.