Warmer Outlook Ahead With Elevated Heavy Rainfall Risk For Parts Of New Zealand

The second half of 2025 is likely to see a wet start, with warmer than average temperatures across all New Zealand, according to Earth Sciences New Zealand's (formerly NIWA) Seasonal Climate Outlook for July to September.

Tropical weather patterns are expected to influence New Zealand over the next quarter, says Earth Sciences New Zealand principal scientist and meteorologist Chris Brandolino.

"There is a high likelihood for tropical and sub-tropical influences, and low-pressure systems, to affect the country over the next three months, leading to potentially significant rainfall and increased risk for flooding, particularly in already-saturated areas. Rainfall is expected to be above normal in the north of both islands, and near normal or above normal elsewhere, except for the West Coast of the South Island, where drier than usual conditions are possible."

Seasonal air temperatures are expected to be above average across all regions of New Zealand for the three-month period, he says.

"So while cold snaps and frost will occur, they are expected to be less frequent than usual."

More region-specific information is available in the latest Seasonal Climate Outlook ( Seasonal Climate Outlook July - September 2025 | Earth Sciences New Zealand | NIWA), which is released each month.

On 1 July 2025, GNS Science and NIWA - both internationally recognised research organisations - merged to create Earth Sciences New Zealand.

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