The frontal system delivering heavy areas of rain moves off the North Island overnight, the South Island stays under its influence for a bit longer however particularily in the east.

Northland, Auckland, Waikato, Bay Of Plenty, Central North Island
Heavy areas of rain ease this evening or early overnight as northeasterlies change northwest, the odd shower with clear spells from then onwards. Some areas may go clear with no further precipitation for a time.
Lows: 10-12

Eastern North Island
Rain clears mid way through the night, northeasterly breezes.
Lows: 10-12

Western North Island & Wellington
Rain, potentially heavy at times eases overnight to the odd shower as northeasterlies change northwest.
Lows: 10-12

Marlborough & Nelson
Heavy areas of rain ease towards dawn tomorrow morning, east to northeasterly breezes.
Lows: 9-10

Canterbury
Rain, heavy at times especially inland about the foothills. Easterly breezes.
Lows: 6-7

West Coast
Rain about North Westland possibly heavy at times easing mid way through the night, drier further south with thick high cloud. Easterly winds.
Lows: 7-8

Southland & Otago
Periods of rain, heavy at times especially about coastal Otago. Easterly breezes.
Lows: 4-8

WeatherWatch.co.nz