Severe Weather Outlook
Issued: 9:54am Tuesday 9 Dec 2025
Valid Thursday 11-Dec-2025
A weak ridge persists over the North Island, which keeps a subtropical low pressure system to the northeast of the North Island well offshore. Meanwhile, a front, which is followed by a change to strong southwesterlies, brings areas of rain to the southern and eastern South Island.
There is minimal risk of severe weather.
Valid Friday 12-Dec-2025
A strong southwesterly flow spreads northwards over New Zealand.
There is minimal risk of severe weather.
Valid Saturday 13-Dec-2025
Southwest winds ease as an area of high pressure moves onto the country from the Tasman Sea.
There is minimal risk of severe weather.
Valid Sunday 14-Dec-2025
A large high over New Zealand moves eastwards, allowing a north to northeast flow develop, with winds becoming strong in exposed parts of southern New Zealand.
There is minimal risk of severe weather.
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 Tuesday, 09-Dec-2025
Issued: 8:12am Tuesday 9 Dec 2025
A combination of afternoon and early evening heating and wind convergence bring a few showers to the central North Island with a low risk of thunderstorms. The risk of thunderstorms is considered moderate however about and near the Hawke's Bay ranges, also Taihape and southern Taupo, with localised rainfall rates of 10 to 25 mm/h and small hail. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during this time.
Valid to Noon Wednesday, 10-Dec-2025
Issued: 9:15am Tuesday 9 Dec 2025
A front moves northwards across Fiordland in the early morning, with a low risk of thunderstorms. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during this time.
Valid to Midnight Wednesday, 10-Dec-2025
Issued: 9:19am Tuesday 9 Dec 2025
Afternoon and early evening heating and wind convergence bring a low risk of thunderstorms to the central North Island, also from inland South Canterbury to Dunedin, and inland Marlborough, as depicted on the chart. The risk of thunderstorms is considered moderate however for the ranges of South Canterbury and inland North Otago, with localised heavy rain and small hail. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during this time.
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.