Heavy rain and strong winds are forecast to lash lower parts of the country this weekend.
MetService said a "significant autumnal change" was expected to arrive in the second half of the week, and is warning that up to 250mm of rain may fall on parts of the West Coast.
It said after a fine Monday and Tuesday, a change in the Tasman Sea was unfolding, with a large area of low pressure set to arrive in New Zealand on Wednesday.
"While we've been enjoying the light winds and lack of rain for the last while, these crisp still mornings are about to end and the wetter side of autumn is set to come back with a bang," MetService meteorologist Braydon White said.
Rain was expected to set in for western areas of the South Island from Wednesday, with a gradual increase in showers for northern parts of both islands.
MetService has issued an orange heavy rain warning for the ranges of the Westland District from 9pm tomorrow.
The heaviest rain was expected on Thursday morning, with 20 to 30mm per hour possible.
MetService said there was a minimal chance the warning would be upgraded to red.
Streams and river could rise rapidly in Westland and there could be surface flooding and slips, it said.
A heavy rain watch was also issued for Fiordland north of Doubtful Sound and the headwaters of Otago and Canterbury's lakes and rivers.
MetService said on Thursday most areas in the northeast would experience rain with western and northern parts receiving "heavier bursts".
"The wetter weather brings along much warmer temperatures," White said.
"Overnight temperatures will be as much as 15°C warmer than we've had recently, with minimums in the mid-to-upper teens widespread across the North Island."
A second, deeper area of low pressure was expected to bring more heavy rain and strong winds for the South Island on Friday.
The system would bring a change to strong southwesterlies going into the weekend, with large swells possible for western coastlines, MetService said.
