A cold southwesterly airflow lies over New Zealand today, a cold front within this flow hits the lower South Island around midday then pushes northwards to reach the lower North Island overnight.

Northland, Auckland, Waikato & Bay Of Plenty
Any early showers clear then expect mostly sunny weather. Northland doesn’t see showers clear till midday however then some sun breaks through. Later in the evening or overnight a few showers start to move in again from the west. Southwesterly winds, gusty in the morning Auckland northwards.
Highs: 14-16

Western North Island (including Central North Island)
Any morning showers clear then expect sunny spells with easing southerly winds, in the evening a few showers start to move in again with freshening westerly winds. Rain overnight.
Highs: 10-15

Eastern North Island
Showers, mainly about eastern coastal fringes, easing and clearing in the afternoon although a lingering shower may hang about Gisborne till evening. Just inland conditions are mainly dry with morning cloud breaking to sunny areas which then increase. Cool southwesterly winds die out in the evening. Overnight southwesterly winds freshen up about the Wairarapa bringing further showers, reaching Hawkes Bay by dawn on Sunday.
Highs: 12-14

Wellington
Any morning showers clear then sunny areas develop, southerlies tend northwest in the afternoon. Overnight a southerly change brings further showers.
High: 12

Marlborough & Nelson
A mainly sunny day with some high cloud, a few showers may move through overnight, more so for Nelson. Light winds tend northwest in the afternoon for Marlborough, expect west to southwest winds otherwise.
Highs: 12-13

Canterbury
Early mid level cloud breaks to some sun and high cloud, a few showers develop later in the evening as southwest winds freshen.
Highs: 9-11

West Coast
Mostly sunny, high cloud increases however with rain moving into Fiordland during the morning then pushing northwards during the afternoon and evening as southwesterly winds freshen.
Highs: 8-12

Southland & Otago
Morning high cloud then afternoon southwesterly winds freshen bringing a burst of rain initially then easing to showers. Snow flurries gradually lower to 300m at night.
Highs: 8-11

By Weather Analyst Aaron Wilkinson – WeatherWatch.co.nz