With meteorological autumn just two sleeps away, Kiwis are being warned about an "unsettled" start to the season with snow on the way for some.
Meteorological autumn begins on Friday in New Zealand and NIWA is warning a storm will arrive shortly after.
NIWA says there is the potential for a "deep low" near the South Island on Monday, which could bring heavy rainfall, strong winds, colder temperatures, big waves and some snow.
But in the lead-up to meteorological autumn, NIWA said things are "looking pretty good" over the next few days, except for a southerly change which will come through the lower North Island and parts of the South Island on Wednesday bringing a few showers for Wellington, Marlborough and northern Canterbury.
NIWA meteorologist Seth Carrier also warned a "handful" of showers could be on the way for the northern Waikato.
MetService is also warning about the chance of potential thunderstorms for parts of the North and South Islands.
The Thunderstorm Outlook by MetService shows an upper trough will move to the east of New Zealand on Wednesday but it remains "unstable" over central parts where showers or thunderstorms are expected.
MetService said there is a "moderate risk" of a few afternoon and evening thunderstorms about the Nelson/Tasman region and near the Richmond Range on Wednesday.
"Any thunderstorms that develop will be accompanied by localised heavy rain and small hail," MetService said.
The forecasting agency said there is also a "low risk" of a few afternoon and evening thunderstorms in southern and eastern North Island areas from Hawke's Bay and the central high country to Wairarapa.
But the rest of the country should see fine weather on Wednesday with temperatures in the mid-twenties for most of the North Island.
The southerly change will see Wellington only reach 18 degrees while in the South Island, most places see temperatures in the low twenties or high teens.
MetService short forecast for Wednesday
Northland and Auckland
Fine spells and isolated light showers.
Waikato to Taranaki, including Coromandel, Bay of Plenty, Taupo and Taumarunui
Mostly fine, but one or two showers from afternoon.
Gisborne and Hawke's Bay
Fine at first. Showers spreading north this afternoon.
Taihape and Whanganui to Wellington, also Wairarapa
Showers.
Buller and Nelson
Mainly fine at first, but showers developing from late morning, possibly heavy with thunderstorms about the ranges this afternoon and evening.
Marlborough and Canterbury
Patchy rain or drizzle this morning, then showers, possibly heavy with thunderstorms about the Richmond Range this afternoon and evening.
Otago and Southland
Cloudy with a few showers this morning. Long fine spells this afternoon and evening.
Westland and Fiordland
Mainly fine.
Chatham Islands
Mostly cloudy, with showers from around noon.
