Tuesday is turning into a scorcher for South Islanders.
Temperatures already hitting 23C in Blenheim and Christchurch as a mini heatwave sets in over much of the Island.
Alexandra in Central Otago is forecast to hit 26C today and tomorrow, and Invercargill is expected to hit 25C.
MetService meteorologist Sarah Haddon said the blast of heat was caused by a high sitting to the east of the country.
Haddon said it was unusual for the high to stick around for several days and cause such a prolonged increase in temperatures.
"A heatwave is when we expect temperatures 5 or more degrees above the usual, for five days in a row," she said.
She said Invercargill in particular was experiencing unusually high temperatures.
If the city hit 25C today it would become its hottest October temperature on record.
The heatwave wasn't gracing the whole of the country but most regions were experiencing warmer weather.
Whangarei, Hamilton, Auckland and Tauranga were all sitting around 20C about noon, as was the Wellington region.
The high passing close to the country will create showers in the north and some areas down south, too.
Nelson and Kaikoura are due for a sprinkling, and Auckland, Bay of Plenty and Coromandel are also forecast for brief rain today and tomorrow.
According to Metservice, a rise in temperatures when paired with cooler sea temperatures will also likely create sea fog in southern areas like Otago.
Weather Watch says a low in the Tasman Sea will slowly approach New Zealand towards the end of the week, bringing a heavier dose of rain and a drop in temperatures.
Heavy rain will mostly affect the West Coast of the South Island.