Temperature highs in those areas range from 13C to 15C.
MetService meteorologist Sarah Haddon said a complex and relatively slow-moving low pressure system moving over the country the past few days had reached Auckland late yesterday afternoon.
The main centre of that pressure system is now just to the east of New Zealand.
"That western side of that low is [bringing] those really strong southwesterlies that are covering Auckland and Northland - since yesterday evening and overnight," she said.
"But it's slowly pulling further away. So for today - in general - almost every forecast is an improving or increasingly better weather trend.
"For Auckland and Northland, there will be strong winds throughout the day. But it will slowly get a little bit [better] than it was."
There will, however, be times when the wind could pick up - particularly in parts of Northland and the northern parts of Auckland.
Anyone heading to tomorrow's All Blacks versus Tonga game, in Hamilton, should take a raincoat.
The MetService says "a few showers" could affect the game. Southwesterly winds are also expected, but they should ease in the evening.
People in the central North Island can expect rain most of today. Those will turn into showers later this evening.
It will be a rainy morning in Wellington and there is a possibility of heavy rain later. A high of 11C is expected in the Capital.
Further south, Canterbury is in for showers and southwesterly winds. Snow flurries to 600m are on the cards, according to WeatherWatch.
WeatherWatch analyst Aaron Wilkinson said: "A few flurries may make it down to 400m later in the day, but amounts will be minimal and taper off.''
Snow flurries to 500m are forecast in Southland and Otago and it will be a mostly sunny day about South Westland. Those in North Westland will get some morning showers before high cloud takes over.
"A few showers may linger about Buller through till evening,'' he said.
ROAD SNOWFALL WARNING:
There is a road snowfall warning for Lewis Pass (SH7) that is valid until 11am and motorists are encouraged to keep an eye on alerts before they travel.
"There is a chance that rain could turn to snow for a time about the summit of the road during [this] morning, but little if any snow is expected to settle on the road."
Whangaparāoa had winds gusting up to 90km/h between 7pm and 10pm yesterday, while winds of about 80km/h were recorded across Auckland between midnight and 1am.
"We also have some gales along the Marlborough and Wairarapa coasts."
Northern fire communications shift manager, Colin Underwood, said they had been called out to 15 weather-related incidents in around the Northland and Auckland regions overnight.
"It was mostly trees down and powerlines arcing,'' he said.
Despite those call-outs, none were deemed particularly serious and crews had not been called to any homes damaged as a result of the wild weather, he said.
Flooding in the Te Hauke area of Hastings caused disruption on parts of State Highway 2 - between Te Aute and Te Hauke - last night.
At 9pm, police sent out a plea to motorists to delay travel, if possible, or to avoid the area completely as emergency crews responded.
Today's weather
Whangārei 15C high, 9C low. Occasional showers with possible thunderstorms and hail this afternoon. Gusty southwesterlies.
Auckland 14C, 9C. Showers with possible squally thunderstorms and hail Strong southwesterlies.
Hamilton 14C, 4C. Showers, some possibly heavy with hail, easing this evening. Gusty southwesterlies easing by this afternoon.
Tauranga 15C, 7C. Morning rain easing to a few showers, clearing in the evening. Westerlies strong at times.
New Plymouth 13C, 4C. Showers, some possibly heavy with hail, easing this evening. Gusty southwesterlies easing.
Napier 13C, 6C. Rain, possibly heavy, easing to a few showers this evening. Southwesterlies strengthening in the evening.
Whanganui 13C, 7C. Periods of rain, chance heavy. Southerlies.
Wellington 11C, 6C. Rain gradually easing. Strong southwesterlies, possibly gale in exposed places.
Nelson 13C, 4C. Mostly cloudy with showers, clearing this evening. Southwesterlies.
Christchurch 11C, 3C. Mostly cloudy with showers. Strong southwesterlies, rising to gale in exposed places this afternoon.
Dunedin 10C, 5C. Mostly cloudy with a few showers. Southwesterlies - strong about the coast.
