The hottest days are due to hit the country at the start of next week when temperatures are set to soar to as high as 40C across the South Island.
The mercury hit a whopping 37C yesterday in the small Canterbury township of Waiau, and MetService today warned even higher temperatures are in store, as foehn winds are tipped to sweep over the Canterbury Plains, parts of Otago and Christchurch after the weekend.
Temperatures have soared to the late 20s and early 30s for days on end across Canterbury and north and Central Otago, and Wanaka is expected to be in a meteorological heatwave.
Niwa today said temperatures were likely to rise to the upper 30s and nudge 40C in eastern districts on Tuesday.
MetService forecaster Brian Mercer said the dry, warm winds would make Monday and Tuesday "exceptionally warm".
"They look like they are going to be the hottest days.
"Alexandra is due to get 35 and Wanaka will hit 24 and into Tuesday all centres will be heading in to the late 20s and early 30s and some could go a great deal higher," he said.
Christchurch is forecast to reach 34C on Tuesday.
It won't be as hot in the north but even some Wellington suburbs are expected to reach 31C.
"Across the Wellington region, Lower Hutt and Wainuiomata will be getting into the 30s on Monday. Wainuiomata is expected to reach 31C."
The north is continuing to suffocate under a blanket of humidity and temperatures that barely shift between night and day.
Auckland and Tauranga have endured balmy night-time lows of 22C and 23C - after daytime highs little more than 5C higher.
The warm tropical air will continue to flood across the North Island for the next four days, bringing little respite from the discomfort.
The month is shaping up to be the hottest in New Zealand history.
Niwa yesterday released preliminary data showing January's average maximum temperature was tracking well above record levels as the hottest month ever and the largest difference from average temperature since records began in 1909.
