A fine morning is expected on Saturday morning for Anzac services, but the clear skies won't hold for the rest of the long weekend.
MetService said most dawn parades will be dry thanks to a a high pressure system across the country, blocking wetter weather in the Tasman Sea.
It will be a chilly start to the day for many, with inland areas such as Hamilton, Taupo, Palmerston North and Christchurch dipping as low as 6C.
Northland, Auckland, Coromandel and the West Coast may have the odd shower.
MetService meteorologist Emma Blades said once the sun came up, it would be a warm day for most.
But rain and cloud makes its way up the country over the rest of the weekend, with heavy falls likely in western areas, and strong winds in many places.
Meanwhile, the New Zealand Transport Agency is advising motorists to plan ahead and allow plenty of time to reach dawn events.
Thousands are expected to turn out for 100-year commemorations, which could lead to delays, said highway manager Brett Gliddon.
"There'll be more traffic on the road than there usually is this early in the morning.
"Some roads around parade routes will be closed and this could affect your travel route. People should check ahead and also consider using public transport to avoid the higher traffic volumes."
Heavy traffic is also expected as holidaymakers head away for the long weekend, and Mr Gliddon said congestion was expected on the Northern Gateway Toll Road, north of Auckland.
Lane restrictions on the Te Atatu interchange of the Northwestern Motorway could also cause delays.
"Although traffic volumes will be lower due to the long weekend there are still likely to be significant delays."
In Wellington, NZTA said traffic would be disrupted from Friday lunchtime as roads closed for the Anzac parade.
Large crowds were expected at the Pukeahu National War Memorial Park for Anzac Day, he said, and people planning to attend were advised to arrive early, and plan for limited parking and delays.
Extra public transport services are being put on for the Dawn Service including trains to Wellington Station and shuttle buses to Pukeahu National War Memorial Park.