Dunedin has hit 25degC, making it the warmest centre in the country ahead of forecast wild weather tonight and tomorrow.
The southern city hit the unseasonably warm mark at 11.30am as MetService warned the balmy weather would not last for long.
A MetService spokesman said an active front, preceded by a strong northwesterly flow, would move north over the lower South Island tomorrow.
It is forecast to bring wind gusts of up to 130kmh and heavy rain to inland Otago, Clutha, Southland and the headwaters of the Canterbury and Otago lakes and rivers.
The winds were likely to reach severe gale force about the Southern Alps in Otago and Canterbury.
Waka Kotahi has this morning issued a wind warning for Raes Junction in inland Otago advising motorists to take extra care in high sided vehicles and on motorcycles.
The rain was expected to be particularly heavy in the headwaters of Otago lakes and rivers, where a heavy rain warning has been issued from 11pm tonight until 11pm Thursday.
MetService says the nature of the front means there is some uncertainty about when and where the heaviest rain will hit but is forecasting 200 to 350mm about the divide, and 100 to 140 mm further east that could cause flooding.
Fiordland (north of Doubtful Sound) is also in line for a soaking where up to 350mm could fall between 6pm today and 11pm tomorrow.
Otago, including Dunedin, has been placed on a 24 hour heavy rain watch from noon Thursday. The heaviest falls are expected as the southerly front arrives.Severe gale northerlies gusting to 130kmh were also expected in exposed parts of Fiordland, as well as Southland and Stewart Island between 6am today and 2am tomorrow.
In Otago, severe northwesterlies were expected to gust to 120kmh between 10am today and 2am tomorrow.
"Strong wind gusts could damage trees, powerlines and unsecured structures.
"Driving may be hazardous, especially for high-sided vehicles and motorcycles."
On Friday, the front was expected to move north over the central and upper South Island, he said.
