Weather: Warm temperatures incoming, subtropical air, moisture for latter half of January – Niwa

Warm temperatures are on the way for the latter half of January with subtropical air and rain expected to descend over New Zealand through to March.

The National Institute of Water and Atmospheric Research (Niwa) said a low-pressure system over the Tasman Sea would “act like a gear to bring warm temperatures down from the tropics” late in the month.

It should coincide with Wellington and Auckland Anniversary days this month and Nelson Anniversary Day and Waitangi Day next month, and the beginning of the new school year.

However, Niwa said there was an “enhanced potential for rain events linked to the tropics and sub-tropics” through March.

Cooler than average temperatures (🔵) will continue for much of the country in the coming days.

However, note the area of clockwise spin that forms in the Tasman Sea around 19 January. This is low pressure that will act like a gear to bring warmer temps from the north (🟡). pic.twitter.com/hrHEkQ7MQ6

— NIWA Weather (@NiwaWeather) January 13, 2025

“The risk of occasional heavy rain events remains distinctly possible, particularly as the season progresses,” it said.

In the meantime, though, Niwa said cooler-than-average temperatures would continue for most of the country over the coming days.

MetService meteorologist Surprise Mhlongo said cool temperatures were expected to stick around this week, especially in the east, thanks to the southerly flow driven by a high-pressure system currently dominating New Zealand.

“Western areas and the lower South Island continue to be the best places to be this summer, with Wānaka temperatures forecast to average 28C this week while the West Coast basks in sunshine,” Mhlongo said.

It has been cooler than usual for this time of the year for most across New Zealand. Here is how different from normal the average maximum temperatures were in the first 10 days of 2025.

Cool temperatures continue in the east early this week. However, warmer temperatures are… pic.twitter.com/T7v1UkpSyq

— MetService (@MetService) January 13, 2025

MetService said temperatures in the past few weeks had been “cooler than usual for this time of the year” compared with temperatures last year.

In Auckland, recent temperatures have been -0.8C below the average of the same time last year. In Gisborne, it’s been -4.7C colder than last year.

Christchurch has been -4.5C cooler than this time last year, while towns on the West Coast were the only ones to see temperatures warmer than last year. Hokitika was 2.1C warmer than the same time last year and Milford Sound was 2.9C warmer.

Auckland’s week ahead promised conditions of 23C and fine tomorrow, 25C and partly cloudy on Thursday and Friday, 24C and partly cloudy with rain developing on Saturday and 25C and rainy on Sunday.

Raphael Franks is an Auckland-based reporter who covers breaking news. He joined the Herald as a Te Rito cadet in 2022.

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