Timaru looks likely to have broken January weather records.
Niwa meteorologist Ben Noll said that as of Tuesday morning, the mean minimum temperature for January was 14.2degC, which was 2.5degC above the long-term average.
“And that’s also the warmest so far, since records began in 1885.”
The mean high temperature was 17.8degC, which was 1.8degC above average for the month, while the average maximum temperature was 22.4degC, .8degC above average, Mr Noll said.
Timaru’s highest temperature for the month, as of Tuesday morning, was 32.1degC recorded on January 16.
The town’s record high was 41.3degC, on February 6, 2011.
A “roller coaster” weather pattern was now on its way for eastern parts of the South Island.
While today’s temperature was forecast to be in the low 20s, the mercury is expected to drop further tomorrow – to 16degC – a stark contrast to the high 20s and early 30s experienced across the district over recent days.
“I think it will be a real shock to the systems,” Mr Noll said.
“It’s [going to be] a very busy weather week as a whole for New Zealand, but especially the South Island.”
That weather would bring cool temperatures, rain and wind, MetService meteorologist Brian Mercer said.
“We’ll have very, very strong winds and some rain with it,” he said of the tropical cyclone which was expected to move in from the Tasman.
“[It is] likely to cross over the South Island during Thursday, then move off during Friday.
“Early Thursday morning there’s going to be some rain developing with potential heavy falls [and] gusty northwesterlies later on as the low tracks overhead.”
By early afternoon those winds were expected to change to southwesterlies and by Friday heavy rain would ease to showers.
Mr Mercer warned people to take care as roads could become slippery during that time.
He also advised people to secure their belongings to prevent them from blowing away, and clearing drains so they could cope with heavy rainfall.
A Timaru District Council spokesman said unsecured items such as trampolines could cause damage or injuries during significant wind events.
“It’s important in advance to make sure items such as these are secured and to stay indoors if the wind gusts are severe.”
Despite a rough end to the week, summer’s biggest fans need not fear the sudden change in weather would not mark the end of summer, as temperatures were expected to warm up again, Mr Mercer said.