Very unstable for some North Island regions today bringing thunderstorms and downpours, northwestern parts of the South Island may have a thunderstorm or two also (Buller). Cool for the eastern South Island with southeasterlies.

Northland, Auckland, Waikato & Bay Of Plenty
A mix of sun and cloud, isolated showers develop in the afternoon. Some may become heavy south of Auckland with thunderstorms. Showers ease later on. Light winds then afternoon sea breezes.
Highs: 22-24

Western North Island (including Central North Island)
Partly cloudy, showers develop in the afternoon becoming heavy with thunderstorms, drying out overnight. Light winds tend south to southeast around midday.
Highs: 18-22

Eastern North Island
Partly cloudy, showers develop becoming heavy with thunderstorms. Rain south of Napier becomes heavy meanwhile Gisborne becomes dries out overnight. Winds from the east tending southeast later in the day south of Napier.
Highs: 18-22

Wellington
Showers or some rain with southeasterly winds.
Highs: 17-19

Marlborough & Nelson
Mostly cloudy with a few showers, the ranges of Nelson and Tasman may have an isolated heavy fall / thunderstorm in the afternoon, drying out at night. Southeasterly winds.
Highs: 17-21

Canterbury
Cloudy with showers, there may be some morning rain. Southeasterly winds.
High: 15

West Coast
A mix of sun and cloud, north of about Greymouth expect a few showers, showers may become heavy in the afternoon with thunderstorms then clearing later. Light winds.
Highs: 20-22

Southland & Otago
Chance of a morning shower for Southland then sunny spells break through, Otago has a mostly cloudy day with the odd shower till afternoon. Southeasterly winds.
Highs: 13-16