The weekend's calm sunny skies will not last the week, MetService says.
Light winds and calm conditions over the past few days helped create frosts along with fog patches which have continued into the week.
"For many spots Monday and Tuesday will be dry with plenty of sunshine. The cloudiest places are likely to be on the West Coast with some rain as well,'' said MetService meteorologist John Law.
But as active systems move northwards across New Zealand this week, wet and windy weather is expected to move up the South Island and onto the North Island on Wednesday.
WeatherWatch head analyst Philip Duncan said Wednesday would be colder in the South Island and Thursday chillier for most of New Zealand.
"Then conditions warm back up on Friday before a likely colder change moves up New Zealand starting in the south on Saturday and spreading everywhere by Sunday afternoon,'' Mr Duncan said.
Another front is set to approach the country later in the week, with further heavy rain expected for the West Coast and severe northwest gales possible in eastern regions from Wairarapa to Otago.