New Zealand is in for an unseasonably warm weekend, with temperatures expected to reach 20 degrees in some places, forecasters predict.

A "lingering'' anti-cyclone would bring an improvement in the weather this weekend, but a spell of rain was likely for the second week of the school holidays, MetService predicted.

"The weekend will be great for outdoor plans with a lot of dry weather around,'' meteorologist Daniel Corbett said.

A WeatherWatch forecast predicted "plenty more'' cloud in Auckland, but much warmer temperatures on the whole.

"This weekend we're talking about highs, possibly as much as 20 degrees - in the depths of winter,'' said WeatherWatch head analyst Philip Duncan.

The change will be welcomed, considering snow to sea level was being predicted just a week ago.

But it won't last for long, with a spell of wet weather likely to arrive in the second week of the school holidays.

A westerly flow around the anti-cyclone could mean cloudy spells and some damp weekend weather for the west coasts, especially in the South Island.

A low over the Tasman Sea would send that rain north by the middle of next week, MetService said.

But the weather should settle and become drier by the end of the week.

- APNZ