A westerly airflow lies over New Zealand today with various troughs pushing in from the Tasman Sea, therefore we have plenty of wet weather in the west, drier in the east. A vigorous front pushes in from the west overnight.

Northland, Auckland, Waikato & Bay Of Plenty
Showers, rain moves through late afternoon Auckland southwards then eases as northwesterlies change westerly.
Highs: 16-18

Western North Island (including Central North Island)
Rain, more persistent for a time in the afternoon with a chance of heavy falls and thunderstorms, easing evening. Gusty north to northwesterly winds.
Highs: 12-17

Eastern North Island
High cloud, some rain spreads from the west into Wairarapa during the afternoon, clearing evening. North to northwesterly winds.
Highs: 16-20

Wellington
Rain, more persistent for a time in the afternoon, easing in the evening. Strong to gale northwesterly winds, strongest after midday.
High: 14-15

Marlborough & Nelson
Rain, more persistent for a time around midday as a front moves through then easing back, clearing evening. Gusty northwesterly winds, strong to gale about the Sounds.
Highs: 12-15

Canterbury
Morning widespread rain in the high country, high cloud elsewhere then breaking to afternoon sun, gusty northerly winds (more so for Nth Canterbury). A brief southwesterly flick up the coast in the afternoon could bring a shower or two. Overnight heavy rain moves back into the high country with some rain spreading eastwards.
Highs: 9-16

West Coast
Rain with heavy falls and possible thunderstorms, easing from afternoon as northerlies tend westerly. At night northerlies strengthen again with further heavy falls, thunderstorms and hail.
Highs: 8-14

Southland & Otago
Morning spits or showers clear then expect sunny spells, spots of rain again overnight. Light north to northwesterly winds, afternoon southwesterlies for a time about coastal Otago.
Highs: 10-12