Relief after a dry summer for farmers on the North Island's east coast

More than 100 millimetres of rain is predicted to fall in Gisborne and Hawke's Bay before midnight.

NIWA meteorologist Chris Brandolino says just 30 millimetres of rain will significantly help.

He says that would bring soil moisture levels to where they should be for this time of the year, keeping in mind March usually runs at a deficit.

Brandolino says more rain than that could lead to some surface flooding.