El Niño has been officially declared, with meteorologists warning it could develop into one of the strongest events on record, bringing notable weather changes and economic challenges across New Zealand. Earth Sciences New Zealand (ESNZ) and associated experts report that the climatic phenomenon, originating in the tropical Pacific Ocean, has begun altering weather patterns and is expected to intensify over the coming months.

According to ESNZ forecasting principal scientist Chris Brandolino, the event is currently in its early stages but is likely to strengthen through the July to September period. There is an estimated 80% chance that El Niño will reach or surpass strong intensity levels, exerting significant influence on New Zealand’s climate. The event is projected to peak during the summer of 2026-27.

Weather impacts are expected to be geographically varied. The West Coast, Southern Alps, inland Otago, and Southland are forecast to experience near-average or slightly above-average temperatures and increased rainfall. These regions may also see rising soil moisture levels and river flows, with the likelihood of heavy rain and strong winds increasing later in the winter and particularly into spring.

In contrast, eastern parts of the South Island—including eastern Otago, Canterbury, and Marlborough—are predicted to face drier and warmer conditions. Temperature variability, including marked temperature swings and windy periods, is likely to grow during the winter and spring seasons. Rainfall in these areas is expected to be below or near normal levels, raising concerns about reduced soil moisture and groundwater recharge. This could challenge sectors dependent on consistent water supply, especially agriculture.

Canterbury, in particular, enters the event following an unusually dry period. Christchurch recorded its driest month on record in May, and combined with forecast stronger westerly winds, evaporation rates are expected to rise, compounding moisture deficits. Meteorologists and scientists caution that the persistence and severity of dry conditions could strain agricultural production, influencing feed availability and costs.

Experts highlight agriculture as the sector most directly affected, with downstream impacts anticipated for food processing, transport, and regional businesses. Lincoln University climate adaptation economist Professor Anita Wreford noted that the economic consequences hinge on the event’s duration, geographic extent, and farmers’ access to water and supplementary feed. While irrigation systems may mitigate some rainfall shortfalls, widespread drought would limit agriculture’s resilience by constraining feed movement across regions.

Further economic repercussions could emerge through increased food prices domestically and potential fluctuations in export markets, as El Niño influences global food production. Electricity prices may also be affected if lower rainfall reduces hydroelectric generation, necessitating greater reliance on costlier fossil fuel sources. Nevertheless, these outcomes depend heavily on precipitation patterns and how hydro-lake levels respond.

Some scientists emphasize uncertainties in predicting exact El Niño impacts, noting that no two events are alike. Association of Scientists co-president Troy Baisden suggested that this El Niño could surpass historical precedents, potentially making traditional forecasts less reliable. Climate change is expected to modify the event’s behavior, possibly amplifying impacts such as wetter conditions in the west and hotter, drier spells in eastern regions.

While the Reserve Bank previously estimated that a strong El Niño could reduce New Zealand’s GDP by nearly 0.4% within a year, these figures are not predictive for the current event. Monitoring soil moisture, river flow, and pasture growth in the coming months will be critical in assessing the evolving scale of the impacts on both the environment and the economy.