Severe Weather Outlook
Issued: 10:20am Saturday 20 Sep 2025
Valid Monday 22-Sep-2025
There is moderate confidence of warning amounts of rain in the Richmond and Bryant Ranges(including the Rai Valley) in the early morning, and moderate confidence for Taranaki Maunga. There is low confidence of warning rain for southern Westland and Fiordland, and for the Tararua Range. There is low confidence that severe northwest gales will affect the Marlborough Sounds, Wellington and southern Wairarapa, in the morning.
Valid Tuesday 23-Sep-2025
There is low confidence that a warning will be required for heavy rain for parts of Tasman and Nelson Districts, also northern Marlborough, the Tararua Range, Taranaki, Waitomo and parts of the North Island central high country.
Valid Wednesday 24-Sep-2025
Valid Thursday 25-Sep-2025
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, 21-Sep-2025
Issued: 7:23pm Saturday 20 Sep 2025
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.