Dig out the flannelette sheets and the hot water bottle tonight because it's going to be the coldest night of the year.
MetService have predicted it will drop to 3C tonight and 5C tomorrow night before warming up later in the week.
The cold nights and lower day temperatures (13C today and tomorrow) were caused by a low pressure system that originated in the Southern Ocean and moved up the country, said MetService meteorologist Daniel Corbett.
He said tonight's low of 3C would be the coldest the region has faced so far this year. Until now, the lowest overnight temperature was 7C and that was felt on May 8, 12, 24 and 25.
Mr Corbett said the first band of cold air passed over the North Island last night and the second band was set to make its way over the country today.
"With the strong south-westerly wind it is going to feel disgusting in Tauranga [today]," Mr Corbett said.
"As the wind begins to develop, it will contribute to the overnight low of 3C and it's going to be a bone-chilling start to the day."
Tauranga will get "quite a little blast of cold weather" today and tomorrow before temperatures begin to climb back up to the late teens, Mr Corbett said.
The cold temperatures would be felt across the country, he said, with snow predicted to fall on the volcanoes and the Desert Rd.
"It's going to feel very wintry and it's probably normal for this time of year, although it's come a bit later this year than last. Last year we had already had some snow and some frosts as far north as the Waikato ... but this year we've had a lot more northerlies which bring warm weather and rain, and not as many southerlies, which bring the cold air up from the south."
Mr Corbett said the low weather system that was due to pass over Tauranga would have "quite a bit of a bite" but the sunshine forecast for later this week would help to restore temperatures to around 18C.
The weather forecast for this weekend could still change but at this stage Saturday is expected to be fine with a high of 19C before rain sets in on Sunday afternoon.