While cooler sea surface temperature anomalies were observed again in the equatorial Pacific and areas in the Southern Hemisphere, much of the Northern Hemisphere was warmer than average for January 2023.

+ Data from ERSSTv5 at https://ncei.noaa.gov/products/extended-reconstructed-sst.

Extended Reconstructed Sea Surface Temperature (ERSST)

The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly analysis of SST data derived from the International Comprehensive Ocean–Atmosphere Dataset (ICOADS). The dataset can be used for long-term global and basin-wide studies and incorporates smoothed local and short-term variations.

National Centers for Environmental Information (NCEI)