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Auckland sweltered yesterday in the hottest temperature in more than 130 years - straight after a record-warmest night - but in the south temperatures struggled into the mid-teens.

MetService records show the mercury hit 32.4C at Whenuapai Air Base about 3.30pm, equalling the previous hottest day, recorded at the Auckland Domain in February 1872.'s thermometer went one better, recording an unofficial 34C in West Auckland - a temperature that was fuelled by a hot nor'wester.

WeatherWatch head weather analyst Philip Duncan said although the humidity in Auckland was lower yesterday than on other days, the intense heat and sunnier skies meant it felt more like 38C.

Meanwhile, it was a different story in other parts of the country yesterday. Christchurch and Dunedin only made it to 16C, while Wellington was a pleasant 21C and New Plymouth 22C.

The East Coast was hot with Gisborne on 29C and Napier on 30C.

Heavy rain warnings for the central North Island have now been lifted after the downpours eased.

Auckland's record temperature followed the highest overnight low for February since records on that began in 1961. The temperature did not drop below 22.1C between Wednesday evening and yesterday morning.

And as the mercury soared, Aucklanders did their best to cool down - either by staying indoors with the airconditioning working overtime or taking to the beach and pools for a refreshing dip.

Even at 6pm the eastern bays had clusters of swimmers and sunbathers, despite a low tide and a buffeting easterly.

The weather changed dramatically last night, with a downpour at 8pm. That rain, combined with a northwesterly wind, gradually brought the temperature down.

It was expected to fall drastically early today, with humidity levels also dropping significantly.

But yesterday afternoon, tourists were feeling the humidity.

At Mission Bay, Henning Schuldt from Germany said he had "no option" but to go to the beach, as Auckland's muggy weather provided an uncomfortable contrast to the crisper climate of his homeland.

A group of seven Russian exchange students didn't even make it to the sea, stripping to their underwear to dive into the fountain.

Many Aucklanders chose to stay inside to avoid the heat, emerging only in the evening.

Stas Christyakov, an employee at Movenpick Mission Bay, said he had avoided the outdoors all day. "I sweated far more than usual today. I'm only surviving work by making regular visits to the walk-in ice-cream freezer."

Sisters Paris and Narelle Goebel ventured down to the beach at 6pm, having spent the day in front of at fan at home. "Far too hot to be outside," said Narelle. "My ice cream had melted before I left the shop."

Staff at some Auckland resthomes said the elderly were suffering. A spokeswoman at the Rosaria in Avondale said many residents coped by taking extra cool showers and resting indoors.

At the Auckland SPCA's base in Mangere, chief executive Bob Kerridge said the heat was more of a problem for people than pets as animals seemed to have better inbuilt coping mechanisms than their owners.

However, it was a timely reminder that pets should always have plenty of water and shade to prevent them from overheating.

MetService weather ambassador Bob McDavitt said the hot, humid weather would stick around for the rest of the month. The warmest time of year is usually the first week of February, but humidity stays high until the end of February.

Sea surface temperatures, which make the air muggy with water vapour, peak in late February or early March.

Normally, humans cool down when sweat on their bodies evaporates into the air.

But overnight humidity in Auckland this week hovered around 100 per cent - the point where the air is saturated and sweat cannot evaporate from skin.

Several other places in the North Island had nights of record or near-record warmth this week, including Kumeu, Whitianga, Paeroa, Tauranga airport, Te Puke and Whakatane.

The hottest daytime temperature this month was in Culverdon, Canterbury, where it reached 38C.

The hottest temperature ever recorded in NZ was 42.4C during a heatwave in Rangiora, Canterbury, on February 7, 1973.

Despite the soaring temperatures, Auckland Airconditioning managing director Glenn Clark said fewer people were hiring units than in previous years.

"It's a sign of the times - people are willing to suffer through it. We have got a lot of elderly people suffering, but it's the elderly who are more inclined to be careful about their spending."