Wellington is expected to be windier than usual, with strong northerlies in the morning.
But the skies are set to open above the South Island, with heavy rain expected on the West Coast and a strong wind watch in areas downwind of the ranges.
Rain is expected in Christchurch and Dunedin, with scattered showers set to hit most of the country as the front moves northwards on Thursday.
"Thursday looks very showery, with widespread scattered rain for most places," Oosterwijk said.
Wellington is expected to have a few showers in the morning coupled with strong northerly winds, and showers in the evening.
Rain will also pelt Christchurch on Thursday, before clearing up the following day.
Oosterwijk said the unpredictable weather isn't out of the ordinary for Spring.
"Spring is one of the most changeable season in weather, I wouldn't say this is unusual," she said.
The temperatures are all very average for this time of year and weren't especially out of the ordinary, she said.