Temperatures have reached 34C in one part of the country as a heatwave continues to make life uncomfortable for schools and outdoor workers.
Just after 4pm, the hottest spots were Kawerau on 34C; Wainuiomata, on 33.5C; and Taumaranui on 33.2C.
In Taupo, the road surface temperature reached 60C - hot enough to cook eggs, Metservice said.
Auckland reached 30C today, with some parts of the city close to all-time temperature records.
The hottest spots today are forecast to be inland, with Taumarunui and Te Kuiti both looking at a maximum of 34C.
Yesterday the warmest places around the country all occurred out east, with Napier and Blenheim both reaching 35C to top the lot.
MetService meteorologist Angus Hines said today the weather situation was slightly different, with the high pressure squirting out to the east of New Zealand directing an easterly onshore flow into some eastern areas.
This flow would cool these spots by up to 8C or 9C compared to yesterday, although they would still reach the mid-20s.
The other result of this flow was that central and western spots would heat up a lot from yesterday.
Some places, such as Levin, could be 12C warmer than yesterday, and it was likely many places will be into the 30s.
Hines said the same weather from the long weekend would continue throughout this week.
Hot air would continue to move over the Tasman Sea, unloading a barrage of sticky weather.
Overnight lows on Monday did not drop much below 20C across the country, MetService meteorologist Philippa Murdoch said. Auckland only got as low as 19.9C, while the top spot was Kaitaia on 21.7C.
This came after a roasting Sunday night in the Nelson region, when Richmond set a new record for the highest minimum temperature at 24.3C.
Niwa said the heatwave was expected to peak on Wednesday and Thursday, with maximum temperatures of 36C plus possible.
The Post-Primary Teachers' Association has offered guidance to students and teachers heading back to school in the sweltering heat.
The guidelines stated an acceptable working temperature was 19–24C in summer.
But acceptability would depend on factors including size of classroom, humidity level, availability of heating and air conditioning, and the subject taught.
Those experiencing uncomfortable workplace temperatures could the issue with their workplace health and safety representative or call the local PPTA field officer.
Those trying to beat the heat shouldn't be afraid to run plug-in fans in fear of running up the power bill, Consumer NZ technical writer James le Page said.
"Most plug-in fans have a relatively small electric motor [50-60W] so the usage isn't too bad," he said.
"A 60W fan running for four hours a day will cost around $2 per month with power costing 0.26c/kWh.
"If you have one running while you sleep for eight hours then it's $4 [a month]."
MetService meteorologist Tui McInnes said the hot weather was in part caused by last week's heatwave in Australia.
"What that's done is it's helped to warm the surrounding Tasman Sea, as well as warmed the air up itself."
He said as the air moves over the Tasman from Australia it stays warm, because it's moving over warm ocean.
"If it was over colder ocean the air would cool down a bit as it transports."
"It's not so much the sun that's impacting the temperatures, the air itself is quite warm."
As well as this, New Zealand has a high pressure system sitting over it.
"That brings calmer, settled conditions, which allow the sun to nudge those temperatures even higher."
The hot weather could be defined as a heatwave because a number of places country-wide were forecast to meet the threshold, McInnes said.
As defined by the World Meteorological Organisation, a heatwave is five consecutive days with maximum temperatures 5C above average for the month.
In the North Island, Tauranga, Whakatāne, Te Kuiti, Taumarunui, and the Hutt Valley are on track for a heatwave as are Blenheim, Kaikōura and Ashburton in the South Island.