Cloud is likely to ruin what has been some perfect weather for parts of the country as children head back to school this week.
But the front should disappear in the major cities including Auckland and Wellington - in time for Waitangi weekend.
"We definitely had some pretty nice weather over the weekend and there will be glimpses of that, but there is going to be a lot of cloud around this week, MetService meteorologist Tom Adams said.
The front wil start in the lower South Island tomorrow morning before building up in the western areas, bringing rain.
Adams said there would be cloud in the western parts of the North and South Island and rain was expected everywhere - except Northland - tomorrow morning.