Christmas Day could bring showers and partly cloudy weather across Otago, according to a MetService 10-day forecast issued yesterday afternoon.
But it was too soon to get a ''firm'' forecast for the big day, and much could change, meteorologist John Law said.
''At the moment, high pressure looks to be the main feature over the country from next weekend in the lead-up to Christmas, with the return of northerlies across the country.''
The sun shone over the South Island on Sunday, due to a broad area of high pressure blocking rain from moving south.
But today would be a different story, Mr Law said.
''The next system to move across New Zealand isn't going to encounter the same situation, so we are expecting the rain to reach right down to parts of the South Island,'' Mr Law said.
After a distinctly cool start to the month, temperatures this week look set to climb into the high 20s for some spots.
''A light northeasterly will be keeping spots closer to the east coast a little cooler and with a touch more cloud.''
Another MetService meteorologist, Georgina Griffiths, said Christmas Day in New Zealand could be hit-and-miss, weather-wise.
Out of the six main centres, Dunedin had been both the pick of the bunch and the worst of the lot in Christmases past, she said.
In 1975, a cold southerly meant Dunedin struggled to reach 9.9degC, while in 2009, northwesterlies pushed the temperature up to 32degC.
''Some years, a high arrives in time for Santa,'' Ms Griffiths said.
