December is fast approaching and while that means summer is coming, parts of the South Island are in store for freezing temperatures.
Areas of inland South Island will be close to 0 degrees around 1am on Saturday morning, forecaster WeatherWatch says.
The Southern Ocean is to blame for pushing the odd cold southerly over the country.
"We're seeing short bursts of cold air due to a much stormier Southern Ocean this spring," WeatherWatch head forecaster Philip Duncan said.
"A colder southerly on Friday will be quickly followed by high pressure on Friday night/Saturday morning, allowing cold air to sink inland and temperatures to approach freezing for some."
But for most areas, it's still too mild for frosts, WeatherWatch says.
"Northern Southland, part of Central and western Otago and Canterbury high country do have some risk. But the warm weather during the day will help lift soil temperatures further."
Daytime highs in Southland will reach 15 degrees on Saturday.
"But we can't rule out a light frost patch - or at least some ice on the roof of any vehicles parked outside at night. Any frosts will be very light."
MetService warns there will be showers with potential thunderstorms and hail in the east of the South Island.
"As the low moves away to the east on Friday, it allows a cooler southwest change to move over the country," MetService Meteorologist Stephen Glassey said.
"The cooler air left behind from the southwest change could make for a frosty start on Saturday for inland parts of the lower South Island.
Some Overnight Lows Friday Night/Saturday morning:
Te Anau: +3