More rain fell between 8pm and 11pm than had fallen during the rest of December, washing out the live music and lone piper and dampening the fireworks display in the Octagon.
But it only whetted the appetite of those who gathered to see in the new year.
By midnight, several thousand people had gathered in the upper Octagon.
As the 12th chime of the town hall clock sounded, flares lit the rooftop of the Civic Centre.
A wild cheer greeted the first crack of pyrotechnics, which danced through the sky for five minutes.
One last volley of explosions about 12.05pm drew cheers and applause as the air in the Octagon filled with well wishes and people embraced and kissed - 2015 had arrived.
Earlier, 20mm of rain fell and temperatures plummeted from the day's high of 27degC to 12degC.
Dunedin City Council community events co-ordinator Marilyn Anderson said the heavy rain had even affected the fireworks display, with about a quarter of the pyrotechnics left damp and unlit.
But for 11-year-old Jake Remon, it made no difference.
The display was ''pretty awesome'', he said.
Mrs Anderson said she was ''philosophical'' about the night's festivities.
''I'm very pleased with the people who did stay as long as they did in that driving rain,'' she said.
''We made the best we could out of a bad situation. We got half a show and we were probably lucky to get that.''
It was the worst weather for New Year's Eve festivities in the 15 years she had planned them, Mrs Anderson said.
Stallholders were also left disheartened, as the rain kept crowd numbers far short of 20,000 it was hoped would celebrate in the Octagon.
Antoinette Stirling, of Invercargill, did not let the weather affect her mood for celebration.
She had made the trip to Dunedin with her parents from Balclutha to celebrate with her niece, who had recently moved to Dunedin.
The rain was not going to dampen her spirits.
''Mate, we are in Otago. Come on,'' she said of the torrential conditions.
The rain also made life easy for police, who arrested only nine people for minor offences in the city.
The only concern for police was the level of intoxication among some of those in the Octagon, particularly unaccompanied minors.
Some people believed police and other agencies were there to ''babysit'' their drunken teenagers, she said.
''That's always a disappointment.''
Elsewhere in Otago, New Year's Eve passed with few incidents.
Senior Sergeant Ben Butterfield said police were investigating an alleged sexual assault in Queenstown.
Southern district deployment manager Inspector Kelvin Lloyd said crowds in Queenstown and Wanaka were generally well behaved.
In Queenstown, 14 people were arrested for disorder and alcohol-related offences, while in Wanaka, seven were arrested for similar types of offences.
''The vast majority of people have taken on board the police's prevention messages - drinking alcohol responsibly and looking after their friends and mates to ensure that everyone gets home safely from a good night out,'' he said.
The night passed without incident in Waitaki and Southland.
A Fire Service spokesman said Lookout Point firefighters were called to two minor flooding events in Dunedin.
In Alexandra and Lawrence, firefighters were called out to vegetation fires, both started by power lines downed by wind.
