Very Strong La Niña
Duration June 2021 — July 2023
Peak Intensity -2.4 Degrees Celsius

The 2021-2023 La Nina event was the strongest La Nina event on record. La Nina events result in negative sea surface temperature anomalies in the equatorial pacific, as well as increased dry air and wind shear. It caused the 2021 and 2022 Atlantic hurricane seasons to both be very active (especially 2021), and the 2021 and 2022 Pacific hurricanes seasons had less than 10 named storms.

2021-22: The Main Event

After a moderately strong El Nino that formed in mid-2020 dissipated in May 2021, SST anamolies began to "crash" in the Pacific Ocean. By June, SST anomolies in the Nino 3.4 Region had dropped to -0.7 degrees Celsius. By July, it was at -1.4 degrees Celsius. This resulted in a hyperactive 2021 Atlantic hurricane season and a well below average Pacific hurricane season. By December, SST anomalies in the Nino 3.4 region had reached -2.1 degrees Celsius - becoming, by far, the strongest La Nina event on record and the strongest ENSO event since the 2014-16 El Nino. In February, the La Nina peaked with an SST anomaly of -2.4 degrees Celsius in the Nino 3.4 region. In March, the La Nina began to rapidly weaken, but SST anomalies remained negative.

2022-23: Weaker "Modoki" Event

Weaker La Nina conditions persisted throughout 2022 and early 2023, with SST anomalies remaining negative through July 2023, when an ENSO neutral pattern began. This resulted in an active 2022 Atlantic hurricane season, but significantly less active than 2021.