Temperatures are tipped to reach the mid-to-high 20s throughout the coming days, with Invercargill set to be grilled on Friday.
The southern-folk will be treated to a balmy 25C, much higher than their January average of just 19C, and areas of Central Otago will near 30C.
In the west, from Northland down to Wellington, morning clouds can be expected before breaking out into fine weather with isolated showers this afternoon for inland Northland.
Bay of Plenty, Gisborne and Wairarapa will be mostly fine, with isolated showers about Wairarapa and Hawke's Bay from midday.
Nelson and Marlborough are set to be mainly fine also, with isolated afternoon and evening showers about the ranges.
It will become cloudy this morning over Canterbury, with patchy drizzle about the foothills.
Buller to Fiordland will be blanketed with cloudy periods and isolated showers this morning and becoming fine later in the morning.
There will be a few showers near the coast in Otago and Southland before clearing away this morning. Fine and cloudy periods will follow.
There are no weather watches or warnings in place for New Zealand.
A low will approach from the tropics but is expected to move away to the east and should have minimal effect on our weather, Rossiter says.
"The ridge persists for the rest of the week, so nice and settled [weather]."
In the North Island tomorrow, the most exciting weather is expected in the east again and Central Plateau where there will be isolated showers.
And in the South Island, drizzle is expected about the fiords.
Today's weather forecast
WhangÄrei: Fine, some morning cloud. Light winds and afternoon sea breezes. High 25C, Low 14C.
Auckland: Morning cloud, clearing to a fine day. Southwesterlies dying out at night. 23C, 15C.
Tauranga: Fine, cloudy periods from evening. Southwesterly breezes. 27C, 17C.
Hamilton: Fine, some morning cloud. Southwest breezes. 24C, 11C.
New Plymouth: Fine, some morning cloud. Southwesterlies, picking up in the afternoon, dying out at night. 22C, 13C.
Napier: Fine morning, then cloud increasing and southeasterlies, with a shower possible from late afternoon. 25C, 18C.
Wellington: Fine, apart from some morning cloud. Northerlies changing southerly this morning, then dying out at night. 21C, 13C.
Christchurch: Becoming cloudy this morning with a southerly change. Winds turning northeast in the afternoon. 18C, 13C.
Queenstown: Fine. Southerlies, dying out in the evening. 22C, 10C.
Dunedin: Mostly cloudy, but afternoon fine breaks. Southwesterlies, dying out in the afternoon. 18C, 12C.
Invercargill: Mostly cloudy, with a few morning showers. Fine spells increasing afternoon. Westerlies, dying out in the evening. 16C, 9C.