While tomorrow would still be a little cool — Auckland will have a high of 17C, Hamilton 16C, Wellington and Christchurch 13C and Dunedin 14C — it would warm up in the week ahead, Ngamanu said.
The North Island especially could look forward to much improved weather this week.
"In Auckland, there'll be a few showers, but nothing too serious through the week.
"Wellington is looking pretty good. And the [wind] flow is generally coming from a north-west direction ... so it's warmer."
Auckland can expect highs of 18C or 19C through the week, Tauranga will hover around 18C and Hamilton can expect to reach 20C on Tuesday and Wednesday. Wellington will be a bit cooler, with highs between 14C and 17C, before dipping to 12C on Saturday.
Eastern areas were looking to be the pick of places to be, Ngamanu said.
Hawke's Bay, Gisborne and Wairarapa should have good warmth and it will be dry, just maybe a little windy. Napier's daytime highs will soar into the low 20s from Tuesday, with oodles of sunshine, with the same weather expected up the road in Gisborne.
Northern and eastern parts of the South Island will also enjoy a fine and relatively warm week, before a cool change by the weekend.
Christchurch will hover around 20C and 21C from Tuesday to Thursday, but dip to 12C/13C from Friday on.
A low expected to develop over the Tasman Sea will bring rain to the West Coast and the deep south from Tuesday and Wednesday, although its exact impact was not yet known, Ngamanu said.
"Things could change, because it's a way off."
Tomorrow's weather
Whangarei: Cloudy periods with a few spots of rain. 19C
Auckland: Few spots of morning rain, chance evening showers. 17C
Hamilton: Few spots of early morning rain, then fine spells. 16C
Tauranga: Few spots of early morning rain, evening showers. 15C
Palmerston North: Fine. 15C
Wellington: Fine. 13C
Nelson: Fine. 14C
Christchurch: Fine. 13C
Dunedin: Fine. 14C
Queenstown: Fine. 16C
