About 50 to 75 millimetres of rain were forecast for Ottawa-Gatineau, and slightly less to its west, according to rainfall warnings issued for Tuesday and early Wednesday morning.
They ended Wednesday morning.
Environment Canada's forecast gave the higher range for other communities such as Brockville, Cornwall and Maniwaki.
For more westerly areas such as Gananoque, Kingston and Pembroke, it was more like 40 to 60 millimetres from Tuesday morning until that night.
There were no warnings for the Bancroft, Belleville or Deep River areas. Belleville was expected to get around 30 millimetres of rain.
The rain was expected to be heavy at times and could go above the higher-end forecasts if multiple thunderstorms hit, according to Environment Canada.
Ottawa's forecast said there was a risk of a thunderstorm for most of Tuesday. The high was 21 C with the humidity making it feel more like 26, but the temperature should fall to around 16 C in the afternoon.
Wednesday's high is 18 C, but it should reach that fairly early on before falling to 12 C and then further to an overnight low of 6 C. That would be the chilliest night since the first week of June.
Using weather records going back to the 1870s, the most rain Ottawa has recorded on Sept. 13 is 35.6 mm in 1928.