A front pushes northwards over the South Island today bringing heavy rain in the west, spits of rain out east. The North Island is still largely settled today thanks to some high pressure. Very cold air moves in for the South Island on Sunday.

Northland, Auckland, Waikato & Bay Of Plenty
Mostly sunny after any morning fog clears, some high cloud. In the evening cloud thickens in the west then expect some overnight rain. Light winds gradually tend northwest.
Highs: 16-18

Western North Island (including Central North Island)
A mix of sun and cloud, cloud thickens from afternoon with the odd light shower moving into Kapiti and Taranaki. Showers becoming more widespread in the evening with rain moving into the aforementioned areas. North to northwesterly winds freshen, winds may become strong for coastal areas.
Highs: 12-16

Eastern North Island
Mostly sunny but expect some high cloud too, north to northwesterly winds, gusty for Wairarapa.
Highs: 16-19

Wellington
Mostly cloudy, a few spits or showers, more so from afternoon, rain overnight. Strong to gale northerly winds.
High: 15

Marlborough & Nelson
Mostly cloudy, a few spits. Rain moves into Nelson midday, spreading into Marlborough mid to late afternoon. Clearing overnight. Gusty north to northwesterly winds.
Highs: 15-17

Canterbury
Heavy rain in the high country, a few spits of rain spreading eastwards, easing from afternoon as a front moves away to the north. Showers becoming widespread across the plains in the evening. Gusty northerlies at first then winds becoming light after midday.
Highs: 13-18

West Coast
Rain, heavy north of Haast but starting to ease from afternoon as gusty northerlies change southwest, not easing about Buller till evening. 
Highs: 12-15

Southland & Otago
A mix of sun and cloud, a few showers, mainly later in the day. Light northwesterlies, freshening a little from afternoon for Southland.
Highs: 13-15