Niwa climate scientist Gregor Macara said two-thirds of Dunedin's normal monthly rainfall for November was recorded in 19 hours in the city.
Between 5pm on Monday and noon yesterday, 36.6mm of rain fell at Musselburgh in Dunedin.
The normal monthly rainfall for a November in Dunedin was 56mm, he said.
''This is certainly a heavy rainfall event for Dunedin [but] it is not a record-breaker.''
The wettest November day recorded by Niwa in Dunedin was 60.7mm in 1933, he said.
Mr Macara said 64mm of rain had fallen in Dunedin this month, 114% of that of a normal month.
The wettest November in Dunedin was in 1951, when 145.1mm fell.
MetService meteorologist Claire Flynn said the wettest period across Otago in the 19-hour period was between 9pm and 10pm on Monday.
A ''moderate risk'' of thunderstorms was forecast for some inland Otago areas north of Dunedin today.
The thunderstorms could bring hail and between 10mm and 15mm of rainfall per hour.
The sun was forecast to shine across Otago from Friday and stay for the weekend, Ms Flynn said.
Otago Regional Council engineering, hazards and science director Dr Gavin Palmer said council staff had been monitoring river levels since the ''heavy'' rainfall.
Because more rain was forecast today and tomorrow, the rivers could rise again.
The rivers in ''already-saturated catchments'' were likely to rise and council staff would monitor levels and keep the public updated.
The water level of the Pomahaka River in southwest Otago was falling at Leithen Glen but rising at Burkes Ford, he said.
The headwaters of the Kyeburn and Manuherikia had some ''minor overspill''.
The rivers were rising in North Otago but were not expected to hit ''alarm levels'', he said.
The rainfall in Dunedin had not been intense enough to have a significant impact on flood flows in the Silver Stream or the Water of Leith.
An assessment of groundwater levels in South Dunedin revealed no significant ponding, Dr Palmer said.
The groundwater levels were very high but were expected to drop gradually until the forecast heavy rain, and staff would continue to monitor them.
Dunedin City Council acting transport group manager Richard Saunders said part of Portsmouth Dr flooded yesterday morning.
Downer staff were deployed to clear floodwater and monitor traffic for two hours from 6.30am.
A lane motorists used to travel towards the city was closed by flooding.
Consequently, traffic was ''disrupted'' along Portsmouth Dr and on roads on Otago Peninsula, he said.
