Severe Weather Outlook

Issued: 10:14am Sunday 14 Dec 2025

Valid Tuesday 16-Dec-2025

A front moves rapidly northeast from the South Island onto the North Island. Heavy rain and strong northwest winds move northwards with the front.

There is moderate confidence that warning amounts of rain will fall in the ranges of Buller, Tasman, Nelson and northwest Marlborough but low confidence for Grey District, the Tararua Range, Taranaki Maunga, parts of the central North Island, eastern Bay of Plenty and far northern Gisborne/Tairawhiti.

There is low confidence that northwest winds could reach severe gale in exposed parts of Marlborough and Wellington.

Valid Wednesday 17-Dec-2025

The front is likely to move away to the east of the North Island.

There is low confidence that a heavy rainfall warning will be needed for eastern Bay of Plenty and far northern Gisborne/Tairawhiti during the morning.

Valid Thursday 18-Dec-2025

A weak ridge may cover the country.

Currently, the risk of severe weather is considered minimal.

Valid Friday 19-Dec-2025

A front is likely to move rapidly northwards over the South Island. It brings brief heavy rain to western areas, and possibly Southland, Otago and Canterbury but the risk of warning amounts is currently minimal.

There is low confidence that westerly to northwesterly winds will reach severe gale in Wellington, Wairarapa and the Tararua District; and low confidence that southwesterly winds will reach severe gale about coastal North Otago, Banks Peninsula and the Kaikoura Coast.



Low confidence:

A 20% likelihood (or 1 chance in 5) of a warning being issued.

Moderate confidence:

A 40% likelihood (or 2 chances in 5) of a warning being issued.

High confidence:

a 60% likelihood (or 3 chances in 5) of a warning being issued.

New issues of this forecast are made available on this site at or before 16:30 NZST

Thunderstorm Outlook

Valid to Midnight Sunday, 14-Dec-2025

Issued: 6:59am Sunday 14 Dec 2025

There is minimal risk of thunderstorms or significant convection during this period.



Valid to Noon Monday, 15-Dec-2025

Issued: 8:02am Sunday 14 Dec 2025

There is minimal risk of thunderstorms or significant convection during this period.



Valid to Midnight Monday, 15-Dec-2025

Issued: 9:52am Sunday 14 Dec 2025

Monday afternoon and evening a front moves northeast over the central South Island, followed by an unstable showery air-mass. During the afternoon and evening there is a low risk of thunderstorms with heavy rain for the far south of Westland, Fiordland, Southland and Clutha. The risk increases to moderate in the evening and at night for Fiordland and Stewart Island as indicated on the chart and those storms may be accompanied by heavy rain, 10 to 20 mm/h, small hail and strong wind gusts of around 90 km/h. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during this period.



Severe Thunderstorm Criteria

In New Zealand, MetService classifies a thunderstorm as severe if one or more of the following criteria are met:

Heavy rain (from thunderstorms):

Rainfall of 25 millimetres per hour, or more.

Large hail:

Hailstones 20 millimetres in diameter, or larger.

Strong wind gusts (from thunderstorms):

Gusts of 110 kilometres per hour / 60 knots or stronger.

Damaging tornadoes:

Fujita F1 (wind speeds greater than 116 kilometres per hour / 63 knots) or stronger.