However, that won't last long as mostly sunny and fine weather throughout the country is forecast, with temperatures in the late teens to early 20s.
Auckland is set to reach 20C, and Whangarei, Tauranga and Napier are all in for a high of 21C.
"Anzac Day is looking pretty good overall, with a nice ridge over the country," Marsters said.
The only areas with showers forecast are parts of the South Island's West Coast.
Today a band of showers in western areas from Northland to just north of Taranaki will ease for a fine afternoon.
A weak front is moving up the South Island this morning, producing showers in Fiordland and the West Coast, and a few spots on the east coast.
It will bring a southerly change as it moves up the country, but most showers will be offshore.
"It will weaken as it moves north, bringing a change in wind direction but mostly clouds to western areas," Marsters said.
Fine weather is forecast on the North Island's East Coast from Gisborne to Wellington.
The ridge of high pressure pushing in tomorrow will hang around Thursday, producing settled and generally dry weather for most of the country.
However, another series of fronts is set to move into Fiordland and the West Coast Thursday and Friday.
A weak front should move north over the South Island from the southwest on Friday, as a low pressure system over the Tasman Sea approaches northern New Zealand.
"This low coming over from New South Wales is set to bring wet weather to the west of New Zealand," Marsters said.
"There is also a decent rain band coming onto Fiordland and West Coast, and showers for the rest of the country."
Today and Anzac Day weather
Whangarei
Today: Cloudy periods, chance shower from afternoon. Light winds. 20C high, 11C overnight.
Anzac Day: Morning cloud then fine. Southwesterly breezes. 21C high. 11C overnight.
Auckland
Today: Cloudy periods, a few showers. Westerly breezes. 18C high, 13C overnight.
Anzac Day: Mainly fine, chance early shower. Southwesterlies dying out. 20C high, 10C overnight.
Hamilton
Today: Cloudy periods and a few showers. Westerly breezes. 18C high, 7C overnight.
Anzac Day: A fine day apart from morning and evening cloud. Southwest breezes. 20C high, 6C overnight.
Tauranga
Today: A few showers. Fine spells increasing afternoon. Westerly breezes. 19C high, 9C overnight.
Anzac Day: Morning cloud clearing to a fine day. Southwest breezes. 21C high, 10C overnight.
New Plymouth
Today: Cloudy periods and a few showers. Southwesterlies. 17C high, 9C overnight.
Anzac Day: Chance morning shower, then fine spells. Light winds. 18C high, 10C overnight.
Napier
Today: Some morning cloud, then fine. Westerly breezes. 21C high, 7C overnight.
Anzac Day: A fine day. Light winds. 20C high, 6C overnight.
Wellington
Today: Fine apart from some morning cloud. Northerlies, becoming calm at night. 17C high, 10C overnight.
Anzac Day: Morning cloud then fine. Northerlies developing. 17C high, 11C overnight.
Nelson
Today: Fine. Winds mainly light. 18C high, 7C overnight.
Anzac Day: Fine. Southwest breezes. 19C high, 8C overnight.
Christchurch
Today: Fine, high cloud at times. Northerly breezes, turning southeast afternoon. 18C high, 5C overnight,
Anzac Day: Fine. Northeasterly developing afternoon. 16C high, 5C overnight.
Dunedin
Today: A few showers, clearing and becoming fine this morning. Southwesterlies. 16C high, 8C overnight.
Anzac Day: Fine, apart from morning cloud. Southwesterly dying out morning, northerlies developing afternoon. 15C high, 10C overnight.
