A report to the council this week says the lack of radar coverage during last week's flood made it "difficult to confirm whether some rivers had peaked, especially the Silver Stream, Lindsay Creek and Water of Leith''.
Council engineering, hazards and science director Gavin Palmer said the importance of a radar had been conveyed to MetService over time.
MetService initially planned to have such a radar installed in Otago this year but, because of land sales and negotiations, that has been delayed until May 2020.
Dr Palmer said he was confident MetService knew the importance of the project to the region.
In a flood event, a radar would "fill in the gaps'' of river conditions.
Now the council measures rain and flows in various places, but a rain radar could provide information about the variability within rivers and streams.
It also provided more accurate forecasting about where rain would fall.
"It tells us whether rain has actually stopped, or if it's still on the way.''
This would allow the council to be more "anticipatory'' in its actions, which was important for public safety, he said.
Overall the council was "very pleased'' with how flood schemes fared last week.
MetService communications meteorologist Lisa Murray said it was "unfortunate'' the installation of the radar was delayed.
She could not name the preferred site because of ongoing negotiations except that it was about "40km southwest of Dunedin''.
It had a radar in Christchurch and Invercargill.
The beams angled further up the longer away from the radar they got, so Otago readings were "further up'' in the sky and less relevant to what happened on the ground.
It wanted to install the radar in Otago to "serve the people in the region better''.
