Research notes and updates from the team.
During March 2026, sea surface temperature (SST) anomalies weakened further and settled within the ENSO-neutral category across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index at 0.03 °C. Weekly averaged SST anomalies in the Niño 3.4 region were 0.2 °C for the week centered on April 08, 2026, indicating the persistence of values within the ENSO-neutral range.
Read more →During February 2026, sea surface temperature (SST) anomalies weakened further and settled within the ENSO-neutral category across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index at −0.20 °C. Weekly averaged SST anomalies in the Niño 3.4 region were −0.0 °C for the week centered on March 11, 2026, indicating the persistence of values within the ENSO-neutral range.
Read more →During January 2026, sea surface temperature (SST) anomalies remained in weak La Niña territory across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index at -0.54 °C. This marked the third consecutive month that SST anomalies have persisted below the La Niña threshold value.
Read more →During December 2025, sea surface temperature (SST) anomalies remained in La Niña territory across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index at -0.61 °C. This marked the second consecutive month that SST anomalies persisted below the La Niña threshold value.
Read more →In November 2025, sea surface temperature (SST) anomalies crossed the La Niña threshold in the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 anomaly index at -0.68 °C. Weekly averaged SST anomalies in the Niño 3.4 region reached -0.7 °C for the week centered on November 10, 2025, indicating persistent cooler sea surface temperatures.
Read more →During October 2025, sea surface temperature (SST) anomalies remained close to the La Niña threshold over the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 anomaly index at -0.48 °C. Weekly averaged SST anomalies in the Niño 3.4 region were -0.7 °C for the week centered on November 5, 2025, indicating the persistence of cooler sea surface temperatures.
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