The South Island is set to be hit by weather extremes this weekend.
Dry conditions in Southland last month Photo: Southland Regional Council
Heavy and constant rain has been falling in Nelson since early this morning, with 37mm recorded since midnight.
Forecast thunderstorms have not hit the region yet, but a severe weather warning is still in place.
Metservice warned the heavy rain could cause streams and rivers to rise rapidly, with surface flooding and slips possible.
The front was expected to ease later this afternoon.
The Tasman region has escaped most of the stormy weather that has hit other parts of the country in the last fortnight, but the last few days of gentle rain had been a relief for farmers and gardeners who had been subject to water restrictions.
Nelson resident Helen Kerr said it was good to see the hills turn green again.
"After several months of constant sunshine with barely any rain we were beginning to get worried about drought," she said.
The rain now was "abysmal" for holiday-makers but "great for the garden", she said.
The Grey District, which flooded in some places earlier this week, has dodged the latest rain.
At the other end of the island, Invercargill is expected to have one of its hottest days on record tomorrow.
The temperature is forecast to reach 31 degrees, only the sixth time since 1993 that the mercury has got that high.
The hottest temperature the country's southern-most city has ever experienced was 32.2 degrees, nearly a century ago in 1921, Metservice said.
A ridge of high pressure is due to build over the entire country tomorrow, bringing more settled weather.
However, that will be followed in short course by a deep low that will bring rain and wind to much of the country in the middle of next week.