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.
The eastern part of the country should expect finer weather with Napier likely to be one of the hottest places as temperatures there hovered around 30C for the rest of the week.
"The reason for that front is it slows down as it moves north. So that northwesterly flow sticks around for quite a long time but the flip side of that is places further south - instead of getting the northwest ahead of the front - they actually get the front itself."
Adams said large rainfall was expected further south, with severe weather warnings in place for eastern parts of the South Island during Tuesday and Wednesday.
Rain would reach the North Island on Thursday, but was expected to clear to make way for another hot weekend.
Meanwhile Aucklanders revelled in the hot weather over Anniversary weekend with around 12,000 people attending the Laneway Festival at Auckland's Albert Park on Monday as temperatures hit 24C.
By 2pm, fans were relaxing under trees, enjoying a quiet drink in the festival's dedicated wine and beer garden, or grabbing some lunch from the many boutique food options.
Auckland singer-songwriter Fazerdaze kicked off the action on the main stage on Princes St, with The Chills taking over soon after.
Other acts set to perform include Aurora, Tame Impala, Nao, Mick Jenkins and Nick Murphy.