Source: Earth Sciences
Highlights: El Niño conditions have now been confirmed in the tropical Pacific, according to Earth Sciences New Zealand criteria. The event remains in its early stages.
* There is an 80% likelihood for El Niño to reach or exceed strong intensity during the July-September period; impacts on New Zealand’s weather are expected to become more pronounced as the season progresses, peaking in intensity over the 2026-27 summer (for more information: https://earthsciences.nz/news/el-nino-declared-expected-to-intensify-into-one-of-the-strongest-on-record)
* Rainfall is likely to be near normal or below normal for the north and east of the South Island, and the east of the North Island. Rainfall is most likely to be below normal for the remainder of the North Island. The west of the South Island is likely to see above normal rainfall.
* Air temperatures are equally likely to be near or above average nationwide, though cold snaps and frosts are expected. Increasingly windy and variable conditions are anticipated later in winter and into spring as El Niño signals strengthen.
* Two lower-probability factors remain under active monitoring: Sudden Stratospheric Warming events, which have become more frequent in recent years, and the remote possibility of an out-of-season tropical cyclone, historically associated only with El Niño years.