Seasonal Climate Outlook

El Niño continued during January and has around a 100% chance of persisting through April.

El Niño continued during December and has around a 100% chance of persisting through to March 2024.

El Niño continued during November and has around a 100% chance of persisting through summer and an 85% chance of persisting through autumn. Although it will have an important influence on Aotearoa New Zealand’s climate, unusual ocean heat in the western equatorial Pacific and on a global scale has contributed to circulation patterns that are not typically associated with a traditional El Niño.

El Niño continued during October and will likely intensify over the next three months. It has around a 100% chance of persisting during this time. There’s an 80% chance of El Niño continuing through autumn, maintaining an important influence on Aotearoa New Zealand’s climate.

El Niño has officially arrived. A majority of NIWA’s criteria for classifying an El Niño event were satisfied during September. In particular, the Southern Oscillation Index was firmly in El Niño territory, suggesting the atmosphere has become coupled to the ocean.

El Niño Alert criteria continued to be met during July. Central equatorial Pacific sea surface temperatures (SSTs) exceeded El Niño thresholds but the Southern Oscillation Index (an atmospheric indicator) was neutral. Full ocean-atmosphere coupling for El Niño is expected in the next three months, likely persisting through summer.

El Niño Alert criteria was reached during June. Central equatorial Pacific sea surface temperatures (SSTs) exceeded El Niño thresholds, but the Southern Oscillation Index (an atmospheric indicator) was neutral. The ocean-atmosphere system is expected to progress toward El Niño conditions from late winter into spring.

ENSO-neutral conditions persisted during May, but oceanic and atmospheric indicators trended closer to El Niño thresholds. El Niño will continue to develop during winter with the potential for a strong event developing by spring.

ENSO-neutral conditions persisted in April however seas continue to warm across the equatorial Pacific consistent with a developing El Niño. El Niño conditions may arrive during winter.

La Niña ended during March, concluding its three-year run. A dramatic change in tropical trade winds resulted in warming seas across the equatorial Pacific. As of late March, ENSO-neutral conditions were occurring, but El Niño conditions may arrive as early as winter. An El Niño Watch has been issued to cover this potential.

La Niña is expected to transition to ENSO-neutral during March. For Aotearoa New Zealand, this transition is expected to result in more variable air flow, temperature, and rainfall patterns during autumn.

La Niña continued during January, but it has gradually weakened. It will continue to affect Aotearoa New Zealand’s atmospheric patterns in coming months, even as neutral conditions are likely reached in early autumn.

La Niña continued during December and a marine heatwave intensified in Aotearoa New Zealand’s coastal waters with sea surface temperatures (SSTs) 1.1˚C to 1.8˚C above average. La Niña is most likely to ease to neutral by early autumn.

Summer temperatures are about equally likely to be near average or above average in the east of both islands, very likely to be above average in the north of the North Island and the west of both islands, and most likely to be above average in the north of the South Island

Temperatures are very likely to be warmer than average in the north of the North Island and the west of both islands. Above average warmth and periodic humidity is expected from November, a change from the relatively cooler conditions experienced during October.

Temperatures are very likely to be warmer than average in the North Island and north and west of the South Island, and most likely to be warmer than average in the east of the South Island.

La Niña, which restrengthened during August, is expected to be an important climate driver for Aotearoa New Zealand during spring.

Around New Zealand, sea surface temperatures (SSTs) ranged from 0.5˚C to 1.3˚C above average during July, a decrease compared to June. SSTs are forecast to remain above average into spring, which will have an upward influence on air temperatures.

Temperatures are most likely to be warmer than average across all regions of Aotearoa New Zealand. While cold snaps and frosts will occur, their duration and/or frequency may be reduced due to a lack of southerly air flows.

Winter temperatures are likely to be warmer than average across Aotearoa New Zealand. This owes to an expected lack of southerly quarter winds, warmer than average sea surface temperatures, and a continuation of La Niña for at least part of the season.

The atmospheric imprint of La Niña continues to be strong; the Southern Oscillation Index during April is tracking to become the 3rd-highest April value on record since at least 1876.

Temperatures are very likely to be warmer than average in the north and west of the North Island and about equally likely to be near average or above average elsewhere.

March is expected to feature spells of higher than normal pressure in Aotearoa New Zealand, especially during the first half of the month, with drier than normal conditions favoured in the North Island in particular.

La Niña conditions peaked in the equatorial Pacific during January, with a 75% chance for its continuation during the next three months.