A sun-drenched weekend is about to give way to a damp start to the week for some, with a southerly sting to follow.

Much of the country was bathed in sunny, mild weather yesterday as a ridge of high pressure dominated conditions across both islands.

Whanganui took the nationwide high, with 22.3C, ahead of Taumarunui on 21.2C and Whakatane on 21C. In Auckland the mercury reached 20.8C.

But MetService meteorologist Brian Mercer said today early in the week would be characterised by scattered showers around much of the country, especially the west.

It would also be cooler, particularly in the South Island.

"If you were going to summarise, I'd say changeable. It's a spring-like pattern. We haven't settled into a full summer situation but we're not in a full winter pattern."

Today would bring scattered showers around much of the North Island, but they would be isolated in some areas meaning people in some places, such as Auckland, might not see any wet weather at all.

In the southern South Island a weak front would bring rain to Southland, with more isolated falls in Otago and southern Canterbury.

Tomorrow, Coromandel and Bay of Plenty residents can expect morning isolated showers to clear, while from Waikato to Taihape there will be showers in the afternoon and evening.

Isolated showers may also occur in North Otago, Canterbury and the West Coast, Mercer said.

The rest of the South Island, as well as Auckland and the lower North Island will be fine, a pattern that will be repeated on Tuesday.

There will be isolated showers in the North Island's western areas on Tuesday, while showers on the South Island's West Coast will turn to rain.

By late Tuesday a southerly will deliver a brisk reminder of winter for some parts of the South Island.

The cold change is expected to bring snow to 400m to 500m in Central Otago, the Canterbury high country and, possibly, Fiordland, Mercer said.