Rain has already started to fall across parts of the North and South Islands today.
Temperatures are expected to drop over the coming days.
Tomorrow Christchurch and Dunedin should expect a high of 8 deg C, while 16 deg C is forecast in Auckland, and 10 deg C in Wellington.
Weather experts are keeping a close eye on impending rain set to hit Canterbury this weekend.
A Metservice spokesman said heavy rain warnings are likely to be put in place, particularly for the upper South and lower North regions.
There is a risk of flooding and people need to be aware but there is no need to panic at this stage, he said.
"Given the state of the grounds at the moment, it could be an issue.
"Metservice, as the official warning provider, we'll issue any watches or warnings that we deem required."
The area most at risk is north of Christchurch which was not as badly affected by last month's flooding as the south of Christchurch, he said.
It is a similar story in Antarctica - the icy continent has endured some near record-breaking temperatures this week, with Dome Fuji Station (2400km from Scott Base) plunging to -81.7 deg C.
That's almost -8 deg C difference from the coldest ever temperature recorded in Antarctica which was -89.6 deg C at Vostok station in 1983.
Antarctica New Zealand Chief Scientific Adviser Professor John Cottle said the temperature is close to the lowest they will see this year, although July is typically the coldest month so it may drop another degree.
"At bases in the centre of Antarctica, people are unlikely to be able to venture outside, or if they do, they won't be able to have any bare skin exposed to avoid frostbite. With these conditions, it would occur within a few seconds, much like a 'burn' from liquid nitrogen."
He said the cold temperatures are being caused by a "strong polar vortex" which are strong westerly winds that circle Antarctica, trapping cold air near the South Pole and also preventing warmer air from moving south from the tropics.
"When the vortex is stronger it does a better job of preventing exchange of warmer air masses to the north."
