A forecast sweltering heatwave is gripping the country, breaking long-time records and pushing temperatures close to 40C in places.

Today, WeatherWatch NZ has reported recordings of 37C in parts of Napier and Hastings, and 36C in the Marlborough Sounds.

Analyst Philip Duncan said some of those higher temperatures were recorded in more sheltered areas and not across the whole regions. However, generally temperatures in eastern parts of the country were getting up around 33C to 34C.

A cracking temperature of 48C was recorded in Lauder, Central Otago, yesterday afternoon.

Advertisement

But the resident who spotted the number is quick to point out the temperature gauge that caught the whopping figure is on the external wall of a house, exposed to full sun and no wind.

"I'm not trying to be a meteorologist," Wanda Jaggard said.

"I kept watching it, and it kept going up, and at about 3.30pm it peaked.

"And it was really hot, you couldn't be outside - it was just so hot.

"Down here in Central Otago we do have pretty big extremes between the hot and the cold."

Lauder is home to the Niwa Lauder Atmospheric Research Laboratory because of the clear skies and geographical isolation.

Niwa said already in the Nelson region the record for the warmest minimum temperature had been broken, with 24.3C recorded in Richmond.

This was the warmest minimum temperature for the region since records began 157 years ago.

The previous record was 23.7C.

The hottest maximum temperatures so far have been on country's east coast, with Kaikōura hitting 33.4C this morning, and Blenheim and Napier 32.2C, according to MetService.

Gisborne was forecast to hit 34C later today, with similar conditions in Hawke's Bay. In the South Island the hotspots would again be in the east, with Blenheim forecast to reach 35C.

The impressive hot weather was driven by sweltering conditions in Australia.

"The hot weather Australia suffered has helped warm the Tasman Sea and the air above it, helping to transport warm air our way," MetService meteorologist Tui McInnes said.

"Which, combined with settled conditions, paves the way for some hot weather ourselves, especially for those in eastern regions."

The weather can be defined as a heatwave because a number of places throughout the country meet the threshold of one, McInnes said.

As defined by the World Meteorological Organisation, five consecutive days with maximum temperatures 5C above average is a heatwave.

He wera te paemahana i tēnei rā - Warm Temperatures Today

Wera. Hot. It’s the talk of the country. Ka wera i tēnei ra (it’ll be hot today)! The temperatures are set to climb this afternoon with plenty of ka pai (great) weather around the country! You can see in this clip of today’s temperatures that the sea is quite warm too, if you’re wanting an afternoon dip! With this warmer ocean and warmer daytime temperatures, Aotearoa is in for a bit of a warm night too. With all this heat in the strong summer sun, remember to slip, slop, slap and be sun smart! Kia haumaru, stay safe! ^Tui

Posted by MetService New Zealand on Sunday, 27 January 2019

MetService meteorologist Amy Rossiter said warm temperatures were expected over summer, but the length of the extremely warm period was unusual.

"Some parts of the South Island might only get six days over 30C in a year, and this week they could get five or six days in a row," Rossiter said.

The warm air mass is forecast to stick around until Thursday before a front moves up the country on Friday, bringing cooler temperatures.