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In December 2025, the sea surface temperature (SST) anomaly map (top left) generally shows a widespread cooling pattern in the central and eastern equatorial Pacific, indicative of an ongoing weak La Niña condition.

Weak warm SST anomalies were present in the Philippine Sea, as well as in both the monitored northern and southern regions of the Tripole Pacific Index (TPI). Meanwhile, considerable parts of the central North Pacific were considerably warmer, indicative of a negative PDO.

In the Indian Ocean, warmer SST anomalies are observed in the tropical eastern Indian Ocean (i.e., EIO), while slightly warmer SST anomalies were observed in the western Indian Ocean (i.e., WIO), reflecting a neutral dipole pattern. In general, there is no prominent tropical Indian Ocean-wide SST anomaly (i.e., IOBW).

Lastly, the tropical North Atlantic (i.e., TNA) indicates average to slightly cooler SST anomalies.

The maps on the right (top to bottom) indicate the observed SST for December 2025 and the climatological normal from 1991 to 2020, providing context for the SST anomaly maps.