After a frosty night a blanket of fog has descended causing issues on Auckland motorways and spreading as far south as Whanganui.

The NZ Transport Agency said while traffic was "light and flowing" on Auckland motorways, commuters needed to take care on the Northwestern Motorway due to the fog.

Kiwis woke to frosted windscreens this morning as temperatures plummeted overnight under a clear winter night's sky.

At about 5.30am Pukaki Airfield was -7C and Dunedin Airport -6C.

Advertisement

MetService meteorologist Nick Zachar said almost the entire South Island was in the negatives this morning, apart from the West Coast which had a bit of a cloud and rain blanket.

Temperatures in the North Island were slightly warmer, but many areas still got close to 0C.

Even around Auckland some spots dropped to 2C.

Along with the cold temperatures a layer of fog had formed across the North Island, from South Auckland to Whanganui.

"It is pretty widespread, and goes across from New Plymouth to Napier," Zachar said.

A high pressure system forming over the country should lead to a fine day for most places, with just some on and off showers in Wellington and Kāpiti through the day.

A lingering weak front was over the upper North Island this morning.

While it was weakening, it still had just enough strength to produce some showers in Auckland, Coromandel and western Bay of Plenty.

Mixed Weather This Weekend

Mixed Weather This Weekend Tomorrow will see a calmer end to the week’s weather. Unfortunately, a system developing in the Tasman Sea will bring rain and wind to much of the country later this weekend and into the start of next week. The video below shows the progression of the rain band as it passes down the New Zealand. Saturday will be dry for most, but a few showers linger about the country. The rain band moves across late Saturday through Sunday, bringing wet and windy weather to the upper North Island and the west coast of the South Island. With an event like this, it is important to stay up to date with the latest severe weather information at our website http://bit.ly/AllWarnings You can also get the latest forecast for your area at our website http://bit.ly/metservicenz ^Tui

Posted by MetService New Zealand on Wednesday, 11 July 2018

Tomorrow was looking like the day of the weekend, Zachar said.

"That front will completely dissipate Saturday, and it is looking very good."

It wouldn't last though, as a low coming across the Tasman Sea would start to spread a moist northeast flow over the country late Saturday.

The humid system would bump the winter temperatures up, but also bring with it some heavy rain to western areas from Sunday.

On Sunday northeast gales could be severe from Northland to Bay of Plenty and Taranaki. These gales would coincide with king tides, possibly affecting low-lying eastern areas.

There could also be heavy rain over Northland, Coromandel Peninsula, and parts of Auckland.

Later on Sunday and during Monday this heavy rain could spread to Bay of Plenty, parts of Nelson and Marlborough, and potentially Gisborne and over Fiordland and parts of Westland.

On Tuesday, a ridge of high pressure should bring more settled weather.

Today's weather

Whangārei

Few showers from late morning. Northeasterly winds. 16C high, 9C overnight.

Auckland

​ Few showers from afternoon. Northeast developing morning. 15C high, 10C overnight.

Hamilton

Morning fog, then cloudy periods and possible shower. Northeast breezes. 14C high, 6C overnight.

Tauranga

Mostly cloudy with showers. Northeast developing morning. 14C high, 9C overnight.

New Plymouth Few showers from afternoon. Northeast breezes. 13C high, 8C overnight.

Napier Fine, frosty possibly foggy start. Light winds. 16C high, 5C overnight.

Wellington Early frosts, then becoming cloudy, followed by a few showers after midday. Northerlies strengthening. 12C high, 9C overnight.

Nelson Cloudy at times. Northerlies developing by midday. 13C high, 3C overnight.

Christchurch Fine, morning frost. Northeasterlies. 11C high, 0C overnight.

Dunedin Fine, morning frost. Light winds. 10C high, 4C overnight.