Niwa forecaster Nava Fedaeff said Dunedin was forecast to be hotter than usual this summer as a moderate La Nina weather pattern was expected.
Air pressure was forecast to be higher than normal over and to the southeast of the South Island and lower than normal to the northwest of New Zealand, a pattern associated with northeasterly air flow anomalies.
"For Dunedin that means that above average temperatures are expected for summer but also normal or below normal rainfall amounts."
A La Nina pattern could also result in warmer than average sea temperatures.
Marine heatwave conditions have already formed near the northern North Island and northern Tasman Sea during November.
Unusually warm seas in other coastal regions may develop into a marine heatwave over summer.
Dunedin surfer Luke Rogers, of St Clair, said the possibility of a marine heatwave was good news as the sea would be warmer for surfers and he could wear a thinner wetsuit.
However, he would surf in any sea temperature, he said.
"It’s no big deal."
Miss Fedaeff said spring was warmer and drier than normal in Dunedin.
The spring mean temperature at Musselburgh was 11.8degC — 0.9degC above average.
"Which makes it the third warmest spring on record there since records began in 1947."
As of November 29, 115mm of spring rain had fallen in Musselburgh — about 69% of normal.
Fire and Emergency New Zealand changed its fire season status to restricted for the Otago region on Tuesday.
This means a permit is required to light a fire outdoors.
Acting principal rural fire officer Mark Mawhinney said fire crews had been responding to an increased number of out-of-control fires in Otago.
The long-term forecast for Otago was for warm weather.
"Although there is some rain predicted, it will not be enough to keep up with the summer drying that occurs.
"If you get a permit to light a fire this summer, be vigilant.
"Always check the weather conditions to ensure there are no strong winds forecast."
