Powerful and potentially damaging winds are forecast for the North Island, as snow brings road warnings for those in the south.
Heavy fog reduced visibility in parts of Auckland early today, with reports of thick fog in and around Takanini, Papakura and Pukekohe in South Auckland.
MetService meteorologist Alwyn Bakker said there was "some decent fog" just south of the Auckland airport terminals and that visibility had been reduced to 5km.
When visibility starts to get below 10km, that is when it becomes important to authorities, Bakker said.
A spokesman for Auckland Airport said there was no fog at the airport terminals, so flights will not be affected.
Strong wind watch
Aucklanders are waking up to a somewhat mixed day of weather to start the working week, with a few showers forecast this morning before turning to rain this evening and a temperature high of 16C.
But conditions are due to change overnight, as weather experts say a surge of gales will strike the North Island from tomorrow - particularly Auckland and Northland.
MetService has issued a strong wind watch for Northland, Auckland, Great Barrier Island and Coromandel Peninsula, north of Thames and Tairua.
"Southwest winds may approach severe gale in exposed places," the watch says.
The watch is in place from 3am to 4pm tomorrow.
WeatherWatch said a cold front is due to move in tomorrow and will bring a surge of gale-force winds gusting over 100km/h in exposed parts of the North Island.
The winds had the potential to be dangerous and damaging - and could result in power outages and tree branches being snapped off.
"The most exposed will be Northland and parts of Auckland, as the westerly ramps up then turns [southwest] - easing as a southerly by Tuesday night," a WeatherWatch spokesman said.
"Those that don't have gales are still likely to have a period of blustery conditions - but this event does look fairly short-lived.
"Worst of the winds will be hugging the western coastline of the North Island and spreading into northern areas during the day before easing at night."
MetService said rain is expected for the western South Island this afternoon, as the active front over the Tasman Sea pushes into New Zealand.
Rain is on the cards for eastern areas of the South Island and western parts of the North Island later this evening. That rain is due to spread further east overnight and into tomorrow morning.
Road snowfall warnings
A number of road snowfall warnings have also been issued by MetService and will affect Arthur's Pass (SH73), Lindis Pass (SH8), the Crown Range Rd and Milford Rd (SH94).
The Desert Rd has a road snowfall warning in place from 4pm until 10pm tomorrow. Snow is forecast to settle on the road from late this afternoon and evening.
"Expect 1 to 2cm to accumulate about the summit of the road, with lesser amounts down to 900."
Those planning to travel on Arthur's Pass can expect snow to settle on the road from tonight (about 10pm) until tomorrow morning (about 10am).
Between 3cm to 5cm of snow is forecast to settle above 800m, with lesser amounts lower down.
Similar conditions are expected on Lindis Pass; with between 5cm to 10cm of snow expected to accumulate above 800m from 7pm to 5am tomorrow.
Snow is due to settle on Crown Range Rd from late this afternoon (about 4pm) until the early hours of tomorrow (approximately 3am). Between 8cm to 12cm of snow is forecast.
While the warning on Milford Road is in place from 3pm to 11pm tonight. MetService says between 2cm to 4cm of snow is due to accumulate above 800m.
Motorists are advised to keep a close eye on weather updates throughout the day. The next road snowfall warnings update will be issued at 10am.