Law said although it was an “unusually warm” start to the week, colder temperatures are typical for this time of year.
“We had that really mild start to the week that was unusual, with that air coming in from the north and the west. As our winds swung around towards that southerly direction, we saw that cold air coming up,” Law said.
“So a real cold and frosty start for many parts of Christchurch.”
The coldest place in the South Island was Lake Tekapo, where temperatures dropped to -7C.
Law said the cold snap shouldn’t last too long, with temperatures likely to pick up slightly over the next few days.
“I think for many of us, last night was probably one of the colder ones,” he said.
“Once we head in towards Thursday and Friday, our temperatures actually start to pick up again as we start finding some more unsettled weather back towards us.”
Law said although temperatures are set to get warmer, tonight will be another cold one for Christchurch.