WELLINGTON – Meteorologists have warned that a significant El Niño climate pattern is now 95% likely to develop over the next three months, a shift expected to bring drier-than-usual conditions to much of New Zealand and potentially drive global temperatures to record highs by 2027.
The emergence of this pattern marks a critical juncture in the El Niño-Southern Oscillation (ENSO) cycle, a periodic fluctuation in sea surface temperatures and air pressure across the Pacific Ocean. While the immediate impacts are being felt in the South Pacific, the strength of this particular event has international climate scientists concerned about the cumulative effect on planetary warming.
Earth Sciences New Zealand (ESNZ) reports that the tropical Pacific is transitioning rapidly toward El Niño conditions, which are projected to strengthen throughout the winter months before peaking during the summer.
“There is a 95% chance for El Niño conditions to emerge over the June to August period,” the agency stated in its latest Seasonal Climate Outlook.
The phenomenon occurs when sea surface temperatures in the central and eastern Pacific Ocean become warmer than average. This thermal shift disrupts established wind patterns, altering the trajectory of rain clouds and storms across the globe. For New Zealand, this typically manifests as an increase in west and southwesterly winds during the winter, redirecting moisture away from the north and east of the country.
The meteorological forecast indicates a stark regional divide in precipitation. Rainfall is expected to fall below normal across much of the North Island and the eastern regions of the South Island. Conversely, conditions are expected to remain close to normal across the upper South Island and the western coast of the North Island, where exposure to prevailing westerlies is greater.
This projected dryness poses a systemic risk to water-reliant industries, particularly agriculture and viticulture. ESNZ warned that below-normal rainfall will likely reduce groundwater recharge in several key regions, potentially stressing water infrastructure during the transition into the warmer months. Regional and district councils responsible for resource consents and water allocation under New Zealand’s Resource Management Act are expected to face increased pressure to balance competing urban, industrial and irrigation demands if the outlook is realised.
Sector agencies have begun quietly modelling scenarios in which tighter water restrictions, altered planting schedules and increased on-farm storage are brought forward. Drought declarations in New Zealand also trigger tailored government support packages, including financial and advisory assistance to affected communities, meaning Treasury and primary sector ministries will be closely tracking how the climate signal evolves.
While the long-term outlook is drier, the immediate weather has remained volatile. 1News weather presenter Dan Corbett noted that the transition period remains unpredictable.
“The next few months could be quite a ride for the weather,” Corbett said, cautioning that short-lived heavy rain events can still punctuate an overall drying trend.
The developing El Niño has already influenced the onset of the colder season, contributing to an abnormally warm start to winter. In Wellington, the capital has already surpassed its maximum June temperature on record, hitting 19°C within the first two days of the month – a reading more typical of early autumn than the start of meteorological winter.
The dryness has also been evident in the late autumn. MetService meteorologist Gerard Bellam confirmed that Christchurch, Ashburton, Timaru, Whanganui, and Palmerston North were all tracking toward their driest May on record, raising early concerns about soil moisture deficits.
“It’s very warm. A lot warmer than usual,” Bellam said, adding that persistently elevated temperatures can mask emerging drought stress until well into the season.
Despite the overarching dry trend, New Zealand is currently grappling with a trough embedded in a humid northerly flow, which has brought heavy rain and flooding risks to several regions. This specific system is expected to maintain higher nighttime temperatures, complicating planning for local emergency management teams that must prepare simultaneously for flood response and looming water shortages.
MetService meteorologist Ngaire Wotherspoon observed that the timing of this system coincides with the start of the meteorological winter.
“As we hit meteorological winter on June 1, this system is going to bring some quite warm and humid conditions,” Wotherspoon said. “We’re going to be looking at some pretty sticky nights ahead.”
The broader implications of this event extend beyond the South Pacific. Historically, strong El Niño events correlate with an increase in global mean surface temperatures as the ocean releases vast amounts of heat into the atmosphere. The last major El Niño episodes have coincided with spikes in the global temperature record, intensifying scrutiny from climate negotiators and scientific bodies.
The current trajectory suggests that the interaction between this natural cycle and anthropogenic climate change could push global temperatures to unprecedented levels in 2027. Such a spike would complicate international efforts to adhere to the temperature limits set by the Paris Agreement, as ENSO events often create “step-ups” in global heating that are difficult to reverse. Climate diplomats and national governments will be watching closely ahead of upcoming United Nations climate conferences, where progress toward the agreement’s 1.5°C and 2°C thresholds is assessed against the latest scientific data.
The expected decline in severe weather events bringing heavy rain from the north – which have plagued the country over the past year – is viewed by forecasters as a trade-off for the looming risk of drought. For policymakers, that trade-off will likely require early decisions on water management, civil defence preparedness and targeted support for at-risk communities rather than reactive crisis measures once conditions deteriorate.
MetService continues to monitor sea surface temperature anomalies in the central Pacific to determine the ultimate intensity of the peak summer phase, while ESNZ says it will update its outlooks regularly to guide local councils, infrastructure operators and national agencies as they move into what could become a defining El Niño year.
