"For pretty much the whole country it'll be quite a fine day.
"Because we're in the middle of winter and not getting that much heat from the sun it could take awhile for the frost to clear."
Northland to Waitomo, including the Coromandel, Bay of Plenty and the central high country will be mainly fine with areas of early morning frost and fog, according to the MetService.
Showers will develop in Coromandel this morning, and the odd one will spread to northern Auckland and eastern Northland by tonight.
Gisborne and the Wairoa District will also get a few showers. Taranaki, Wellington and Wairarapa will be cloudy this morning with isolated showers.
It will start to turn fine north of Wellington of Wairarapa by this afternoon.
Cloud will gradually increase in Nelson and Marlborough, which will get isolated showers by this evening.
Canterbury's few spots of rain will clear by the afternoon.
Buller and Westland will have scattered showers, but Otago, Southland and Fiordland will be mainly fine with spots of frost or fog this morning.
Cloudy periods and the odd shower will linger around coastal Southland and Clutha.
A front of heavy rain will move over the South Island on Friday. Hefty falls will pelt the West Coast and Central Plateau and snow could come down to 400m in the mountains.
The front will then make its way up the country on Saturday and Sunday, Mercer said.
"We're expecting heavy rain for most parts over the weekend.
"It's not really going to be very pleasant."
Main centres
Auckland - High 14C, low 4C
Hamilton - High 14C, low 0C
Tauranga - High 15C, low 5C
Wellington - High 11C, low 6C
Christchurch - High 11C, low 2C
Dunedin - High 10C, low 3C
