Close to 10mm of rain fell on Whanganui during Monday night, with MetService predicting the worst of it is in the rear-view mirror.
A cold front swept through Whanganui last night, with 9.2mm of rain falling between 3am and 6am.
"It is kind of standard for a run-of-the-mill weather system like this one," MetService meteorologist Dan Corrigan said.
The heaviest of the rainfall was between 3am and 4am, with over 4mm of rain.
"4.4mm of rain an hour is getting close to what we call heavy rain."