That usually means we can expect temperamental weather, but for much of Otago and Southland, the forecast is for a relatively calm and warm start to the season.
MetService meteorologist David Miller said a high-pressure system was expected to build in the South this week, bringing temperatures in the high teens to Oamaru, Dunedin and Alexandra this Friday, Saturday and Sunday.
He said a ridge of high pressure was forecast to cover New Zealand early tomorrow.
However, a weak front was expected to move east over the south of the South Island from tomorrow afternoon to Thursday morning, bringing light or moderate rain or showers.
Any showers associated with that weak front were expected to be brief.
Mr Miller said the ridge should then remain "firmly in charge" over the whole country from Thursday afternoon until Saturday.
A front, preceded by strong northwesterlies, was then forecast to approach the south of the South Island from the Tasman Sea late on Saturday.
At this stage, it was possible northwesterlies could rise to severe gales in exposed parts of Fiordland and Southland, including Stewart Island, on Saturday, he said.
"Wednesday marks the first day of meteorological spring," he said.
"Although spring is usually characterised by fast-moving weather systems, mostly settled weather is forecast for much of the country this week, apart from a few showers in the east of the North Island.
"Morning frosts are also possible in parts of the South Island."
