Freezing start around the country causes crashes, halts trains in Wellington

Icy roads in Dunedin's hill suburbs.Icy roads in Dunedin's hill suburbs on Thursday. Photo: RNZ

By Lauren Crimp of RNZ

Icy conditions have caused multiple crashes and suspended some trains in the capital on Friday morning.

Parts of the country are waking up to freezing temperatures this morning as a cold snap strikes.

At the start of the day it was -3 deg C in Christchurch and Masterton, -2 in Tīmaru, Hamilton and Rotorua, and -1 in Taupō, Napier, Blenheim and Queenstown.

There were "significant disruptions" on the capital's train services, Metlink said.

Icy conditions meant the trains could not draw power from the lines, a spokesperson said.

Kāpiti line services were suspended but were running again by mid-morning, and there were disruptions and delays on the Hutt Valley and Wairarapa lines.

"Metlink is providing bus replacements where possible and service alerts have been sent alerting passengers of the situation and the lack of capacity on buses," it said.

"Once the day warms, it's likely normal services will resume."

☀️Clear skies and freeeeezzzing🧊🥶 temperatures continue across the country, but cloud looms to the west.

This Infrared Satellite 🛰️📡 image shows most of the country is still in the clear this morning, however, thin wispy high cloud is sitting over parts of Northland, as well…

pic.twitter.com/R1gUFyD2WP

— MetService (@MetService)

July 24, 2025

The police are urging Bay of Plenty drivers to extra care on the roads in the region.

A person has been critically injured following a serious crash in Atiamuri, partially closing State Highway 30.

"There have been a number of crashes across the region already this morning with ice creating dangerous driving conditions," police said.

"Please - slow down, watch your following distance, and use your headlights."

Driving conditions are expected to be hazardous in many parts of the South Island over the next few days.

Police say black ice has already formed in some areas and road surfaces are especially dangerous in shaded areas and on bridges.

Freezing in Invercargill, mild on nearby Rakiura

While it was -1 deg C in Invercargill on Friday morning, Rakiura Stewart Island - less than 30km across Foveaux Strait - clocked double digits.

MetService meterologist Devlin Lynden said the stark difference in temperatures between the two centres is a phenomenon called low level inversion - when it's unexpectedly warmer at higher elevations.

He said that was because cool air was heavier and sank at night, pooling in low lying areas like Invercargill.

That doesn't happen on Rakiura because it's more exposed.

A band of cloud is also acting as insulation on the island - and it's windier, mixing air from different altitudes.