A weather system moving across the Tasman Sea will bring a soggy start to 2015, meteorologist John Law said.
Bands of rain are forecast to move from the Tasman Sea across NZ by tomorrow.
"It looks like we will all get a chance to see some wet weather to end the year," Mr Law said. "The timings of these features are going to be critical in determining which parts of the country stay dry when the clock strikes midnight."
Revellers in the north of the country should "keep a raincoat handy", he said, with a front expected to bring cloud and rain in Auckland for the countdown.
The wet weather should clear in Wellington and the upper South Island before midnight, but tomorrow was likely to be blustery during the day.
The wet and windy change comes after scorching summer temperatures over Christmas, with Blenheim peaking at 29C on December 25 and Masterton reaching 27C.
Yesterday brought stunning weather to much of the country.
Alexandra, near Wanaka, was the hottest place to be, with a high of 28C.
Auckland experienced another beautiful day, as temperatures peaked at about 25C in the early afternoon.
Swimmers take the plunge from a wharf at Pilot Bay, with Mt Maunganui (Mauao) in the background.
Hundreds of people headed to the city's beaches.
Despite the beautiful weather in most regions, there were thunderstorms in Taranaki, Wanganui and Taumarunui.
Although those areas will still experience highs in the mid-20s over the next few days, the bad weather is not expected to lift until Friday.
