MetService meteorologist John Law said a front was expected to move across the South Island early on Thursday, bringing strong northerlies and rain/showers for parts of Fiordland, Southland, Stewart Island and inland Otago.
At this stage, the only place that is not expected to have rain is Dunedin.
Mr Law said Anzac Day dawn services were generally cold because they were held at the coldest time of the day, but the injection of a strong northerly wind would warm things up a little.
"Hopefully, for the morning services, we’ll find we are still in some slightly warmer temperatures."
Mr Law said the overnight low for Dunedin on Thursday morning was forecast to be a balmy 11°C, and other parts of the region would go down to 9°C.
Although it was warmer, coats, hats and maybe even an umbrella would still be needed.
But once the sun was up, temperatures would rise quickly to as high as 19°C in Dunedin, Oamaru and Alexandra, he said.
"I think our temperatures might be better in the morning, because they ease off in the afternoon and things will turn cooler when the wind turns more westerly.
"In the latter part of the day, snow will lower to 800m, making the winds very cold around the region."
Temperatures were expected to drop to about 3°C as a result, he said.
