The warm and humid conditions Aucklanders are experiencing are here to stay for the rest of the week, MetService predicts.
"The air is moving down from the tropics over New Zealand and combined with a ridge of high pressure over the North island, it is giving the North Island some warm temperatures," meteorologist Lisa Murray said.
The ridge was also keeping the weather settled.
Temperatures in the evenings would cool off -- but it would still be warm.
However, there would be a chance of showers on Saturday, Ms Murray said.
Today, Gisborne recorded the country's hottest temperature of the day, 30C.
The hot weather would continue in Gisborne for the rest of the week, with temperatures of 30C to 31C, Ms Murray said. "They'll be able to go for a swim or have a barbecue," Ms Murray said.
The capital was windy today, and the temperature hit only 20C.
The fresh northerly wind would continue and strengthen on Saturday, Ms Murray said.
"It will be quite strong on Sunday morning as well, but it will ease off in the evening."
Temperatures on Saturday would hit 22C, and on Sunday 21C.
Christchurch had a warm day today, with temperatures rising to 28C.
Ms Murray said it would be a similar story for the rest of the week, with temperatures fluctuating between 26C and 30C.
Meanwhile, Tropical Cyclone Victor, which is currently south of Niue, is expected to slowly track west over the next few days to Tonga. After that, it is expected to slide southwards.
Ms Murray said the effects could be felt in New Zealand from the middle of next week.
MetService advised anyone living in the northern areas of the country to keep an eye on their website for updates.
The warm weather across the country comes after National Aeronautics and Space Administration (Nasa) announced today that 2015 was the hottest year recorded since record keeping began in 1880.
Global average temperatures last year beat the previous record set in 2014 by 0.13C, Nasa said.
Weather patterns such as El Nino or La Nina, which warm or cool the tropical Pacific Ocean, could contribute to "short-term variations in global average temperature".
A warming El Nino was in effect for most of 2015.
Nasa Goddard Institute for Space Studies director Gavin Schmidt said last year was "remarkable even in the context of the ongoing El Nino".
"Last year's temperatures had an assist from El Nino, but it is the cumulative effect of the long-term trend that has resulted in the record warming that we are seeing," he said.
Weather today and tomorrow
Tomorrow: 26C. Few showers, chance heavy/thundery PM. Light winds.
Saturday: 26C. Fine spells. Chance afternoon/evening shower. Light winds.
Tomorrow: 26C. Morning cloud then fine. Chance of afternoon shower. Light winds.
Saturday: 27C. Fine spells. Chance afternoon/evening shower. Light winds.
Tomorrow: 27C. Fine apart from some morning cloud. Light winds.
Saturday: 28C. Fine apart from some morning cloud. Light winds.
Tomorrow: 21C. Cloudy periods. Fresh northerlies.
Saturday: 22C. Fine apart from some morning cloud. Strengthening northerlies.
Tomorrow: 30C. Fine, with high cloud at times. Northerlies.
Saturday: 29C. High cloud increases, few spots of rain develop. Northerly.
Tomorrow: 27C. High cloud, few spots of rain from afternoon. Northwest.
Saturday: 25C. High cloud, few spots of rain. Northerlies easing.