A ridge brings settled weather to the North Island on Monday meanwhile a northerly airflow over the South Island brings areas of rain or showers in the west and dry weather out east.
For the upper North Island expect cloudy areas, perhaps a light shower or two about Coromandel, Great Barrier Island etc. Winds from the east or northeast. Mostly cloudy skies about East Cape / Gisborne, risk of a light shower at times with easterlies. Sunnier skies for southern parts of the North Island although expect some high cloud, winds from the north to northeast. Some cloud at times for Taranaki and Kapiti however.
A mostly cloudy day for Nelson, showers develop from afternoon. The West Coast has showers, rain about Fiordland with the odd heavy fall moves northwards into North Westland by evening. Dry along the east coast with sunny areas and some high cloud. Mostly cloudy for Southland with the odd shower from afternoon, light winds.
Temperatures in the late teens for most of the North Island, late teens for the eastern South Island (perhaps even cracking 20 in Canterbury). Mid teen temperatures for the rest of the South Island.