"For the North Island it will be mid to late 20s, that will be the trend for the week. Towards the end of the week we will get those muggy nights back.
"But they won't be as bad as what we saw a few weeks ago."
However, a northwest flow would strengthen over the South Island on Monday ahead of a front that would approach from the Tasman Sea.
"There is low confidence rainfall accumulations will reach warning criteria about Fiordland from Monday evening through to Tuesday evening.
"In addition, there is low confidence northwest gales about exposed parts of Fiordland, Southland and Stewart Island may become severe for a time on Monday and Tuesday morning."
Aside from the west coast of the South Island expecting rain, most of the island would have fine weather reaching into the high 20s, Haddon said.
"For the South Island it will be warm with most places in the late 20s as a high.
"There may be a slightly cooler change towards the end of week," she said.
Your weather tomorrow
WhangÄrei: Fine, some high cloud from afternoon. Light southwesterlies.
High 27C Low 14C
Auckland: Fine, but some high cloud from afternoon. Light winds at first, then southwesterlies developing in the afternoon.
High 25C Low 16C
Whanganui: Fine, apart from morning and evening cloud. Light winds, but afternoon and evening westerlies.
High 24C Low 14C
Napier: Fine. Westerlies turning northeast for a time in the afternoon and evening.
High 25C Low 11C
Wellington: Morning cloud, then becoming fine. Northerlies, strengthening for a time in the afternoon and evening.
High 21 Low 14C
Christchurch: Fine, some morning cloud. Northwest breezes developing afternoon.
High 28C Low 11C
Dunedin: Fine, some morning cloud. Westerlies.
High 23C Low 16C
Greymouth: Cloudy periods, chance evening shower. Southwest breezes.
High 19C Low 12C
