Severe Weather Outlook

Issued: 9:09am Sunday 15 Mar 2026

Valid Tuesday 17-Mar-2026

A ridge of high pressure covers northern and central New Zealand on Tuesday, while a front in the Tasman Sea approaches the southern South Island during the second half of the day.

There is minimal risk of severe weather affecting New Zealand.

Valid Wednesday 18-Mar-2026

A ridge of high pressure remains over the North Island on Wednesday, while a front moves northwards over the South Island, while weakening, bringing a period of rain to most South Island areas.

There is low confidence that rainfall amounts will reach warning criteria about northern Fiordland and the ranges of Southern and Central Westland.

Valid Thursday 19-Mar-2026

A ridge of high pressure builds over most of the South Island. A sub-tropical low may move into the area just northeast of the North Island, and although there is some uncertainty regarding the movement of this low, there is currently only a very low risk of it affecting the North Island.

At this stage, there is minimal risk of severe weather affecting New Zealand on Thursday.

Valid Friday 20-Mar-2026

The ridge over the South Island is expected to spread over the North Island during the day.
There is minimal risk of severe weather affecting New Zealand.

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, 15-Mar-2026

Issued: 7:20am Sunday 15 Mar 2026

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



Valid to Noon Monday, 16-Mar-2026

Issued: 7:53pm Sunday 15 Mar 2026

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



Valid to Midnight Monday, 16-Mar-2026

Issued: 7:54pm Sunday 15 Mar 2026

There is minimal risk of thunderstorms or significant convection 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.