Weather: Wet, windy conditions forecast for South Island, expected to move north on Sunday

• Wet and windy weather is forecast to return for much of the South Island by the weekend.
• MetService has issued a series of heavy rain and strong wind watches for the middle and south of the South Island.
• Forecasters say there is a high chance the weather will move onto the North Island on Sunday.

Heavy rain and strong winds are expected to sweep across the South Island on Saturday, moving north on Sunday.

MetService forecaster Surprise Mhlongo told the Herald weather was forecast to be cloudy in the western and fine in the eastern parts of the country today.

However, several heavy rain and strong wind watches for the west and middle of the South Island have been issued from tomorrow until early Sunday.

❗🟡Heavy rain and Strong Wind Watches issued

🌦🌧Rain is expected to increase through the weekend, with the South Island expected to see some significant impacts from Saturday.

🌧💧🌬Heavy rain and strong winds may reach warning criteria, and as a result various areas have… pic.twitter.com/brWFMuvYjK

— MetService (@MetService) May 14, 2025

Watches for Fiordland north of Doubtful Sound and the headwaters of the Otago Lakes and Rivers are forecast to start late on Saturday morning until about midnight.

There is a moderate chance these two watches will be upgraded to warnings.

Heavy rain watches for the headwaters of the Canterbury Lakes and Rivers, Westland ranges, Buller, Tasman northwest of Motueka, and the Grey District ranges are set to come into force from late Saturday afternoon.

High pressure (🔴) will bring settled weather to most of the country over the next few days.

However, an area of low pressure (🔵) will arrive late Saturday or Sunday with a period of rain and thunderstorms ⛈️ before a second area of high pressure returns early next week. pic.twitter.com/8ycgCL7Ktv

— NIWA Weather (@NiwaWeather) May 12, 2025

“Streams and rivers may rise rapidly in some places. Surface flooding, slips, and difficult driving conditions [are] possible.”

There is a high chance the rain watches in Westland and Canterbury Lakes and Rivers will be upgraded to warnings.

A Yellow strong wind watch is forecast to begin for the Canterbury High Country from late Saturday night until early Sunday morning.

There is a moderate chance this watch will be upgraded to a warning.

MetService forecaster Surprise Mhlongo told the Herald the severe weather could move on to the South Island on Sunday.

“The severe weather outlook indicates there is a moderate chance places like the Tararua Ranges might see heavy rain,” he said.

“There is a moderate chance Mt Taranki might see heavy rain.”

Mhlongo said there was also a chance heavy rain could spread across Wellington and Wairarapa.