Weather: Dramatic temperature change incoming for southern NZ as rain, wind set to upset balmy week

After a balmy week, temperatures are expected to nosedive across the South Island this weekend as a cold change currently chilling Australia makes its way across the Tasman. 

According to WeatherWatch, temperatures across New Zealand are likely to remain several degrees above average on Thursday and Friday, with parts of Southland possibly being more than 8C higher than usual. 

But that all changes in the south on Saturday as cold air moves from Australia to New Zealand, meaning centres like Invercargill, Dunedin, and Queenstown may experience temperatures 8C below normal. 

WeatherWatch spotlights Dunedin, which it says has a high in the low 20s on Friday before tumbling to a maximum of about 12C on Saturday. 

However, that dramatic shift won't be felt up north where "warmer airflows linger". Auckland is expected to have a high of around 20C on Saturday, with the temperature swirling around 18C on both Friday and Saturday night. 

"Next week an even colder surge of air from Australia heads to NZ. Overnight lows will be closer to freezing for some inland areas next week – but the unsettled, often windy/cloudy conditions may stop frosts from forming (but worth monitoring)."

The south should also brace for strong winds on Friday, with north-west gales hitting exposed parts, mostly through the Southern Alps, mountain ranges and coastal areas. 

Weather: Dramatic temperature change incoming for southern NZ as rain, wind set to upset balmy week
Weather: Dramatic temperature change incoming for southern NZ as rain, wind set to upset balmy week

"The North Island has a windy few days ahead too but peak winds don’t look quite as intense as the South Island. Still, severe winds are possible in both main islands from Friday to early next week."

Showers can be expected in western parts of both islands. The West Coast is likely to see about 200mm of rain between Friday and Sunday in stark contrast to only about 5mm around Hastings. 

Metservice has a Heavy Rain Warning in place for the Westland ranges south of Otira between 6am and 6pm on Friday. Locals are warned to expect between 70mm and 100mm of rain in that period, with the strongest hitting in the afternoon. 

A number of Heavy Rain Watches have been issued for other western areas in the south, including west of Motueka, Buller and Fiordland.

The forecaster has a Strong Wind Warning out for Wairarapa and the Canterbury High Country on Friday. 

"Strong wind gusts could damage trees, powerlines and unsecured structures. Driving may be hazardous, especially for high-sided vehicles and motorcycles."

Find the full list of warnings and watches here