A southwesterly airflow lies over New Zealand today, a weak front within this flow quickly moves northwards over the South Island in the morning then the North Island from afternoon.

Northland, Auckland, Waikato & Bay Of Plenty
A mix of sun and cloud with southwesterly winds, breezy at times. There may be a shower or two between Waikato and Northland, especially in the west.
Highs: 15-16

Western North Island (including Central North Island)
Mostly sunny with some cloud drifting through at times, risk of a shower late afternoon / evening otherwise mainly dry for most. Westerlies tend southwest around midday. Coastal Taranaki has breezy southwesterlies for much of the day.
Highs: 11-15

Eastern North Island
Mostly sunny, southwesterlies develop early afternoon bringing some cloud. Chance of a shower in the afternoon about the Wairarapa then further north in the evening.
Highs: 14-17

Wellington
Mostly sunny then southerlies develop around midday bringing some cloud.
High: 13

Marlborough & Nelson
Sunny with southwesterlies for Nelson, light winds about Marlborough tending southerly around midday then easterly during the afternoon.
Highs: 14-16

Canterbury
Southwesterly winds freshen in the morning bringing some cloud, chance of a shower also then becoming mostly sunny during the afternoon.
Highs: 9-11

West Coast
A mix of sun and cloud with southwesterly winds developing in the morning.
Highs: 12-13

Southland & Otago
Any early showers clear then mostly sunny, morning southwesterlies then tending westerly around midday
Highs: 11-12

By Weather Analyst Aaron Wilkinson – WeatherWatch.co.nz