MetService meteorologist April Clark said Tuesday would be Whanganui's wettest day this week, but long, fine periods would be few and far between in the next few days.
"A cold front moved over the region on Tuesday, and it's becoming stationary over the North Island Wednesday," Clark said.
"There'll be scattered light rain, about 1.5mm an hour, but it should ease slowly throughout the day.
"That front doesn't actually move anywhere, it just slowly weakens because we have a ridge of high pressure moving over the country.
"Thursday will see a few fine spells, but with afternoon and evening showers, which will be inland and away from the city. There'll be light winds and some sea breezes around the coast."