The wet Waitangi weekend weather has begun as transport officials urge holidaymakers heading out of town to stay safe and avoid creating highways to hell.
Traffic delays, heat, fatigue and noisy children are all factors that could lead to an an accident, warns the NZ Transport Agency.
Rain settled in today across the upper North Island and WeatherWatch head analyst Philip Duncan said showers would strengthen and become more widespread.
He said there was a high risk of rain tomorrow, although Coromandel and the Kaimai Range might break up the wet weather system before it hits the City of Sails.
Most falls are expected in Coromandel and out to sea but there could be some falls for farmers and gardeners at the top of the North Island.
There is always a chance of afternoon rain, as the sticky, humid conditions remain.
"Hopefully, for the holidaymakers, some areas of rain and showers on Saturday clear as the day goes on."
The wettest areas tomorrow will be in Coromandel, east Waikato and western Bay of Plenty. Hamilton should stay dry.
Further south, eastern areas such as Hawke's Bay, Gisborne, Wairarapa and Canterbury could get some downpours.
Sunday and Monday are looking good for most of the country. It's expected to be settled and dry, although humid winds are possible in the east coasts of both islands.
"Sunday for the South Island looks dry. There's a big high-pressure system moving in," Mr Duncan said.
"On Monday, it's the same set-up again. There's lights winds for the South Island. The winds are so light that there could be some afternoon heat showers."
As usually, the risk was greatest around the ranges.
Temperature-wise, it will be hot and humid up north, but the cloud will keep the highs a little lower than they have been, but many parts of the country should push the late 20sC and even the early 30sC.
Areas with sea breezes might have highs in the early 20sC, Mr Duncan says.
And, most importantly, it is looking good for the New Zealand versus Australia cricket in Wellington tomorrow night.
Mr Duncan says there is a 20 per cent chance of drizzle or a late shower because of the humidity and clouds, but the day will be a typical capital day -- dry and still.
"The high pressure's much stronger down there," Mr Duncan says.
Such pressure turns rain to drizzle.
Whatever the weather, the NZ Transport Agency's road safety director Ernst Zollner has asked for care on the roads. He says most people take it easy behind the wheel anyway.
"But a small minority of irresponsible drivers are still speeding, driving after drinking, when they're tired or while they're distracted," he says.
"This puts everyone who uses our roads in potential danger, every single person who gets behind the wheel needs to take responsibility for their driving behaviour, only then will we bring our crash rate down."
Four people died on the road during Waitangi weekend last year.
The agency's Auckland and Northland highway manager Brett Gliddon says planning ahead could make a difference.
"Delays in our usual traffic hotspots will affect some drivers but motorists can avoid the busy times and make their journey a more pleasant one.
"It can make a considerable difference to your travel times if you choose your getaway and return journey times out of the peak times."
He says State Highway 1 between Puhoi and Wellsford is traditionally quite busy, with peak traffic expected to run till 8:30 this evening.
It is likely to get busy again at 8.30 on Saturday morning till 2.30 in the afternoon.
Mr Gliddon predicts traffic could also build for those travelling south on the highway through Maramarua.
"For those heading south on SH1 and on SH2 through Maramarua, there'll be heavy traffic from lunchtime Friday, with the busiest peak from 2pm until early evening."
Heading home again, Sunday and Monday are busy times for those travelling south on SH1 from Puhoi. Heavy traffic is expected from lunchtime until 5pm both days.
"Motorists returning to Auckland from the south on SH2 and SH1 can expect the busiest times on Monday from the middle of the day, so travel early to avoid delays."
Tips for driving safely:
•Ensure everyone travelling with you is wearing a seatbelt
•Watch your speed
•Be courteous to other road users
•Drive to the conditions