Your weather: New Zealand in for wet week, warnings in place for the West Coast

Make the most of the mild weather today as most of the country will see rain as the kids go back to school this week.

Auckland's mild spring continues with a high of 18C on Sunday, but it will be cloudy and with isolated showers and strong northeast winds, increasing from the afternoon.

Similar weather is forecast for much of the North Island, with northerly winds and cloudy periods - the east in for the most sunshine and temperatures in the low 20s.

MetService forecast Tuporo Marsters said those attending the All Blacks match in Wellington this afternoon might want to bring a raincoat with showers forecast, but not an umbrella as they'll be accompanied by some strong northerlies.

The South Island meanwhile will see heavy rain continue in the west - reaching warning levels or over 100mm in 24 hours in some places - and warm temperatures in the east.

Christchurch could reach a high of 22C, and even Invercargill is forecast to hit 20C.

Driving this weather is a complex frontal system, preceded by a strong moist north to northwest flow, approaching the South Island this evening, before moving north across the island Sunday.

This system is expected to bring periods of heavy rain to the west and north of the South Island, and gale northwesterlies about Canterbury High Country, where warnings and watches are in force.

Late Sunday the rain will spread from the West Coast to the North Island, reaching most western areas from Wellington to Auckland and Northland by the end of Monday, with scattered showers in the east.

On Tuesday the rain will shift to the northeast, stretching from Northland to Gisborne, as showers clear to the south.

Wednesday is looking much more settled for the North Island, meanwhile the South Island will experience some wet and cold southerlies.