This week's sunny skies are forecast to slip away today, with rain and heavy falls forecast for the south of the country. The rain will reach the North Island tomorrow, with heavy falls expected in the west.

Sunshine is expected to return in many parts of the country on Anzac Day, but MetService predicts the wet weather would stick around in Northland, Gisborne and Hawkes Bay and the south and west of the South Island early on Monday.

Autumn has been unseasonably warm so far, with MetService meteorologist Lisa Murray saying temperatures had been about 1C or so warmer than average for this time of year.

Auckland and Wellington hit 21C yesterday, and Christchurch and Dunedin were not far behind on 17C. Auckland is forecast to hit 22C on Saturday.