Seasonal Climate Outlook: Nov 2024 - Jan 2025

Outlook Summary

• A La Niña Watch remains in effect, with a little over 50% chance that La Niña officially develops by the end of the year. However, this event is likely to be weak and short-lived and might stay below traditional La Niña thresholds.

• There are indications for more widespread dry conditions than what is typical for La Niña across much of New Zealand, especially at the beginning of the three-month outlook period, rainfall is most likely to be near normal in the east of the North Island, and about equally likely to be near normal or below normal for all remaining regions of the country.

• Chances for more anticyclonic conditions over and to the southeast of New Zealand may lead to dry spells developing, especially in the west of both islands. La Niña-like conditions could on the other hand bring short and intense rain events for the north of the North Island and the eastern parts of both islands. Monitor NIWA35 for updates.

• Air temperatures are very likely to be above average across the country. An increased prevalence of northeasterly winds may lead to more days above 25 C than normal during November-January.

• Coastal sea surface temperatures (SSTs) ranged from 0.55 C to 1.01 C above average during October. Marine heatwave conditions were occurring near the southeast of the North Island and east of the South Island, and to a lesser extent along the west coast of the North Island. Monitor the SST update for updates, which suggests marine heatwave conditions may intensify in the months ahead.

• November-January soil moisture levels and river flows are most likely to be near normal in the east of the South Island. In the west of the North Island, near normal soil moisture levels are most likely, and river flows are equally likely to be near normal or below normal. For all other regions of the country, soil moisture levels and river flows are about equally likely to be near normal or below normal.

• Soil moisture levels at depth continue to be below normal in the east of the North Island while soil moisture is normal in the east of the South Island.

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