Cromwell has hit its hottest spring temperature on record today, a sweltering 33.3 degrees, and the summer temperatures continue through the weekend.

Photo: RNZI / Johnny Blades

NIWA meteorologist Ben Noll said Cromwell's previous Spring record was 32.3° in 2010, but that has been beaten this afternoon by a whole degree, and it may still go higher.

Fourth generation Cromwell fruit gower, Simon Webb, said in the 40 years he has lived in the Central Otago town, he has never experienced weather this hot in November.

"Just blue skies, calm and you can feel the burn in the sun. It's really, really hot. We only swam in the lake a couple of times last year and we've done it three or four times already."

In the last 31 days, the Central Otago town was warmer than 20° on 24 days.

NIWA said an "immense dome" of high pressure has settled over the entire country, and could bring record high temperatures to parts of the inland South Island.

It's also very dry so far this month, after a generally wet 2017 for the country.

Immense dome of high pressure sprawling over New Zealand today ... means record or near-record November temperatures possible in the south & some places could even approach spring (Sep-Nov) records. pic.twitter.com/tZMZ7mhZi1 — NIWA Weather (@NiwaWeather) November 22, 2017

A year ago, Wellington was in the middle of its wettest November on record - 240.6mm of rainfall in the month - and flooding. This month the capital has recorded 17.2mm so far and is tracking for one of the driest November rainfall levels on record.

Christchurch Airport had only 1mm of rain so far this month and is tracking for the driest November since records began in 1863. Lincoln, with 0.4mm of rain, is also tracking toward its driest November since records began there in 1881.

Niwa said the "big dry" is being influenced by La Nina conditions in the Pacific.

Photo: MetService

MetService's official maximum for Wednesday was 29.5° in Wanaka. (MetService does not have a weather station in Cromwell).

Wanaka is set for 29°C today, with high temperatures until next week at least. Wellington, Nelson and Christchurch get to 21° today, the forecast says.

MetService forecaster Gerrit Keyser said Wanaka was about two degrees off its November record on Wednesday. Alexandra reached 28°.

He said there could be the odd isolated shower about the ranges in the next few days, and some cloud in the mornings or overnight.

The MetService says the large high pressure system is forecast to cover the country from Thursday until Monday.