Seasonal Climate Outlook February To April 2025 By The National Institute Of Water And Atmospheric Research (NIWA)

Seasonal Climate Outlook

New Zealand is likely to experience a blend of typical La Niña climate patterns, along with occasional atypical patterns over the next three months, according to the latest Seasonal Climate Outlook released today (Friday 31 January 2025) by the National Institute of Water and Atmospheric Research (NIWA).

A La Niña Advisory is in effect, though weak and expected to be short-lived, says NIWA National Climate Centre Principal Scientist Chris Brandolino, with international guidance indicating around a 50% chance for La Niña conditions persisting through the February to April period. "When combined with atypical characteristics including sea surface temperature anomalies, is likely to mean New Zealand will experience La Niña-like patterns with occasional deviation."

Overall, New Zealand can expect wind from the easterly quarter, ranging from NE to SE flows, along with occasional periods of westerly quarter flows, from SW to NW, for the three-month period, he says. "The north and west of the North Island can expect warmer than average temperatures, with equal chances for near average or above average seasonal air temperatures for most other regions."

Early February weather is likely to be drier than normal, but over the three months through to the end of April seasonal rainfall is forecast to be near or above normal for most regions. However, northern and eastern North Island may see occasional heavy rain events.

Soil moisture and river flows are expected to be near or below normal in most areas. At the same time, sea surface temperatures are forecast to be above average, with a normal to elevated tropical cyclone risk with the potential for an ex-tropical cyclone to pass near New Zealand.

Regional predictions for February – April 2025

The tables below show the probabilities (or percent chances) for each of three categories: above average, near average, and below average. In the absence of any forecast guidance there would be an equal likelihood (33% chance) of the outcome for any of the three categories. Forecast information from local and global guidance models is used to indicate the deviation from equal chance that is expected for the coming three-month period. All outlooks are for the three months as a whole. There will inevitably be relatively wet and dry days, and hot and cold days, within a season. The exact range in temperature and rainfall within each of the three categories varies with location and season. However, as a guide, the “near average” or middle category for the temperature predictions includes deviations up to ±0.5°C relative to the long-term mean, whereas for rainfall the “near normal” category lies between 80 percent and 120 percent of the long-term (1991-2020) mean. 

Northland, Auckland, Waikato, Bay of Plenty

• Temperatures are likely to be above average (50% chance).   
• Rainfall totals are about equally likely to be near normal (35% chance) or above normal (40% chance).  Occasional heavy rainfall events cannot be ruled out as the season progresses.
• Soil moisture levels are about equally likely to be near normal (45% chance) or below normal (45% chance), with near normal (45% chance) river flows likely.

Central North Island, Taranaki, Whanganui, Manawatu, Wellington

Probabilities are assigned in three categories: above average, near average, and below average. 

• Temperatures are likely to be above average (50% chance).   
• Rainfall totals are about equally likely to be near normal (40% chance) or above normal (35% chance).  Occasional heavy rainfall events cannot be ruled out as the season progresses.
• Soil moisture levels and river flows are both about equally likely to be near normal (45-40% chance) or below normal (40% chance).

Gisborne, Hawke’s Bay, Wairarapa

Probabilities are assigned in three categories: above average, near average, and below average. 

• Temperatures are about equally likely to be near average (40% chance) or above average (35% chance).   
• Rainfall totals are about equally likely to be near normal (40% chance) or above normal (35% chance).  Occasional heavy rainfall events cannot be ruled out as the season progresses.
• Soil moisture levels and river flows are both about equally likely to be near normal (40-45% chance) or below normal (35-40% chance).

Tasman, Nelson, Marlborough, Buller

Probabilities are assigned in three categories: above average, near average, and below average. 

• Temperatures are about equally likely to be near average (35% chance) or above average (40% chance).
• Rainfall totals are about equally likely to be near normal (40% chance) or above normal (35% chance).  Occasional heavy rainfall events cannot be ruled out.
• Soil moisture levels and river flows are both likely to be near normal (40% chance).

West Coast, Southern Alps and foothills, inland Otago, Southland

Probabilities are assigned in three categories: above average, near average, and below average. 

• Temperatures are about equally likely to be near average (40% chance) or above average (45% chance).
• Rainfall totals are most likely to be near normal (50% chance). However, periods of unusual dryness are likely, interspersed with rainfall events.
• Soil moisture levels and river flows are equally likely to be near normal (40% chance) or below normal (40% chance).

Coastal Canterbury and the nearby plains, east Otago

Probabilities are assigned in three categories: above average, near average, and below average. 

• Temperatures are about equally likely to be near average (40% chance) or above average (35% chance).
• Rainfall totals are most likely to be near normal (40% chance) or above normal (35% chance). 
• Soil moisture levels and river flows are most likely to be near normal (45% chance).

The full probability breakdown is:

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