MetService says heavy rain and thunderstorms hit eastern Bay of Plenty on Tuesday morning, with 12mm falling in Whakatane inside of an hour.
The forecaster said storms are moving fairly quickly, with the heaviest remaining offshore for now, and should ease by 9am.
The rain was expected to continue in lower North Island and upper South Island, as unsettled weather lingered.
MetService said it would be a soggy afternoon in the eastern parts of Wellington, more fine in the west.
There was a snowfall warning in the Lewis Pass until late Tuesday afternoon, and there was expected to be light rains in Marlborough and Canterbury that night.
Fog in Northland, Auckland and Waikato will clear and be followed by showers.
The western areas of the country should get some sunshine until Friday, but with strong winds in the West Coast, Tasman, Nelson and the Manawatū.
The weekend is looking on the wet side, especially for the North Island and upper South Island, with the potential for heavy rain for some of those areas.
MetService meteorologist Ngaire Wotherspoon said the southeasterly wind should be responsible for the rain and low temperature during the day.