Rain is unlikely to be enough to break droughts in the North Island, as the lower North and South Island experience the first of chill of autumn.
Water restrictions have been extended to communities along Northland's drought-stricken east coast where water supplies risk being contaminated and becoming undrinkable.
Metservice meteorologist Ciaran Doolin said thunderstorms had brought some rain over the North Island today, but most of it was not concentrated in Northland and Waikato, which had been in drought conditions.
"Northland really has not been the focus in the action area," he said. "This frontal feature is looking to move to the northeast and might bring a little more rain in those places, then that will move off this evening."
Hawke's Bay has also been experiencing a dry period, and although the storms might have a chance of restoring more moisture to parched soils there than in either Northland or Waikato, it was largely falling on the northern ranges, Doolin said.
There was expected to be a little more rain for Northland tomorrow, but it was likely to be even less than had fallen today, he said, and the dry conditions were likely to continue through the rest of the week.
Thunderstorms were largely focused on Hawke's Bay, Bay of Plenty, and Taupō, bringing about 130 lighting strikes to the area over the last couple of hours.
He said meteorologists were watching the approach of a high-pressure anti-cyclone nearing the country.
"It may spread some precipitation over Northland but we don't have high confidence."
Meanwhile, temperatures across the South Island, and some of the lower North Island, took a dive this morning.
Doolin said Wellington, as an example, was about 21C or 22C overnight but that dropped by five or six degrees this morning.
He said much of the South Island would experience single-digit temperatures overnight, "in some cases, low single digits".
The cold was expected to be largely focused around Central Otago, with Wanaka and Lumsden seeing minimum temperatures of 3C and Aoraki / Mount Cook getting down to 2C.
Even Christchurch was expected to dip to 6C.
"Not necessarily unusual but we're heading out of summer into early autumn."
He said the largely mild summer meant people might be feeling the effects of the cold more than usual.