Sunday is warmer than average by day in just about every single part of the country all thanks to a sub-tropical flow descending across the nation.

NORTH ISLAND:
East to NE winds for most regions but lighter winds further down the island may help fog generate. Otherwise a mix of sun and cloud today with cloudiest weather in the north east where there will also be a few showers (eastern Northland for example) and maybe a couple of isolated showers between Auckland and Gisborne in that NE flow. Dry elsewhere.
Highs: 12 to 19

SOUTH ISLAND:
Showers turn to patchy rain on the West Coast today and sets in more this evening and overnight with some isolated heavy falls. Showers and/or patchy rain may spillover into parts of Nelson and Southland as well, otherwise fairly dry…and completely dry in the east. Warmer than average everywhere today.
Highs: 8 to 17

– WeatherWatch.co.nz