A ridge of high pressure covers most of New Zealand today, an easterly airflow moving around this ridge pushes over the North Island during the day while a northerly airflow lies over the South Island. And finally a front affects the lower South Island.

Northland, Auckland, Waikato & Bay Of Plenty
A mix of sun and cloud, a few showers about exposed eastern areas like eastern Northland, Great Barrier Island and the Coromandel. Mid afternoon isolated showers develop about most regions with the low risk of a heavy fall then easing in the evening. Easterly winds.
Highs: 23-24

Western North Island (including Central North Island)
Sunny areas and some high cloud, chance of an isolated shower late afternoon / evening about some inland areas. Light winds then afternoon sea breezes.
Highs: 22-25

Eastern North Island
Showers for Gisborne becoming less frequent from afternoon, some sun may even break through. Hawkes Bay sees any morning showers clear then cloud breaks to sunny spells. Mostly sunny for the Wairarapa. East to northeasterly winds.
Highs: 20-22

Wellington
Sunny areas and some high cloud, Northerly winds.
High: 22

Marlborough & Nelson
Sunny areas and some high cloud, north to northwesterly winds.
Highs: 21-25

Canterbury
Sunny and warm, light winds inland and northeasterly breezes along the coast.
Highs: 24-26

West Coast
Rain for South Westland, heavy falls at times especially about Fiordland. Further north expect sunny spells although cloud thickens in the evening then a few light showers may move in. North to northeasterly winds.
Highs: 18-22

Southland & Otago
Some morning sun for Southland, cloud thickens from midday then rain develops mid afternoon.  Otago has sunny areas and some high cloud, a few spots of rain in the evening. North to northeasterly winds.
Highs: 22-25

By Weather Analyst Aaron Wilkinson – WeatherWatch.co.nz