Temperatures are expected to reach 25 degrees or more in part of the North Island today.
The cooler temperatures experienced in the weekend are going to be short lived with predictions of 30 degree daily highs for this week.
A weak ridge lies over the North Island today meanwhile a front in the Tasman Sea slowly approaches the western South Island moving in late afternoon, says WeatherWatch.co.nz
This front in a much more weakened state crosses the North Island on Tuesday, northwesterlies lie over the South Island however a southerly flick moves up through Otago and Canterbury during the day.
"Mostly sunny for the North Island today, a few morning showers in the northeast clear away.
"The South Island has rain or showers pushing into the West Coast, dry and mostly sunny out east.
"A few brief morning showers for the western North Island on Tuesday then sunny areas increase from afternoon, mostly sunny in the east."
Showers breaking to afternoon sunny spells for the South Island's West Coast, showers may not totally clear till evening, says the weather organisation.
"A few showers about Southland and Otago ease during the day, clearing by evening also. Mostly sunny for Nelson, Marlborough and Canterbury."