The official temperatures are in, confirming what we know. It’s cold.

Clear skies this morning saw Rotorua register a low of -3.4C while the temperature gauge dropped to -6.0C at Taupō Airport, according to MetService.

At sea level, Whakatāne dipped to -2.0C and Tauranga to 1.6C.

Tongariro on the Central Plateau fell to -5.8C.

MetService meteorologist Katie Lyons told the Herald that clear skies and a frigid Antarctic air mass had created ideal conditions for severe frosts.

The coldest temperature in the country this morning was -9.7C at Mt Cook - though it felt more like -13C, according to the MetService website.

That was not far off its coldest temperature this year of -11.5C last month.

Even the “winterless north” didn’t escape the polar plunge with frosts in Whangarei this morning and Kaitāia dipping to 0.4C at 6am.

Despite the freezing starts, much of the country could expect sunny, dry conditions during the day, Lyons said.

“We’re very focused on these cold temperatures because it is really cold, but places will see lots and lots of sun about the country.”

The cold snap followed an Antarctic blast that brought snow, sleet and hail to parts of the country on Tuesday, causing travel chaos in parts of the South Island and even snow flurries in Wellington.

While this morning would bring the coldest conditions for much of the South Island, Lyons said parts of the North Island could become even colder overnight into Friday.

Rotorua could expect a low of -4C overnight tonight and a max of 11C tomorrow.

Taupō will drop to -5C overnight tonight, Tauranga -1C and Whakatāne -3C.

The system is tight

Transpower has warned of energy shortfalls between 7.30am and 8.30am as temperatures plunge across New Zealand.

Energy Minister Simeon Brown told Ryan Bridge TODAY the system is tight.

“Normally they would hope to have around 200 megawatts residual … I’m advised it’s around half or just a bit under half.”

Residual is between how much is being generated and how much is being used. Brown said 7.30am was expected to be the peak and if the generators are at maximum capacity, power companies could step in.

“[Transpower] engage with the sector and work through to make sure there’s enough residual in the system.

“If things get tighter there is still controllable load which effectively is people’s hot water cylinders, which distributers are able to turn off for what’s required.”

He said peaks generally lasted 30 to 60 minutes and the turning off of cylinders “wouldn’t be noticed by people at home”.

Transpower said yesterday’s electricity peak was the highest power use ever recorded.