Feeling the heat? You're not the only one as January 2018 looks to be the hottest in New Zealand's recorded history.

And it won't stop there.

Climate scientist Jim Salinger said if the average temperature for the month slides up only half a degree, it may be the hottest month since records first began.

The average January temperature is 17.1 degrees centigrade, the average so far for January 2018 was 19.3C - the hottest since records began in 1909.

The second warmest January was in 1956 when the average was 18.8C.

The last time #Auckland got below 15C was the final night of 2017! You can check max and min temps in your town or city at https://t.co/hnwmGxU1gR and scrolling to the 'Past Weather' heading. Low temps for tonight below ^AC pic.twitter.com/BTFMR2SJnq

— MetService (@MetService) January 20, 2018

Salinger had downloaded the climate data from Niwa's seven stations which were used to calculate New Zealand's average temperature.

The stations are located at Auckland Airport, Kelburn in Wellington, Masterton Airport, Hokitika Airport, Nelson, Lincoln near Christchurch and Musselburgh, Dunedin.

With 10 days left in January, the average temperature was unlikely to drop given there were no "cool southerlies in the weather projections".

"The door to the southern oceans is shut.

"For the next period in the end of the month there is nothing cold coming from the south, the ocean temperature in the South Island is two degrees warmer than average," Salinger said.

There was a possibility also that January could take over February as the hottest month in recorded history.

"It could increase further, what's interesting is if it will exceed the warmest month which was February 1998 at 19.6 degrees."

Behind that was February 2016 at 19.5C.

"Another half degree would make it the hottest month ever, right now it [January] is the third warmest month ever."

In general, temperatures were 0.9C higher than 1909 which showed there had been "a certain amount of global warming".

MetService meteorologist Sarah Haddon said January had seen Invercargill and Dunedin break their hottest temperature records which was a good indication there had been some "unseasonably hot weather this month".

Dunedin Airport hit 34.8C on January 16 and Invercargill Airport hit 32.3C on January 14.

Like January, February this year is also on track to beat records as the hottest in recorded history.