A rainfall warning is now coupled with a flood warning for the Parry Sound, Muskoka and Haliburton regions.
The Ministry of Natural Resources says anyone in low-lying areas that have seen flooding in the past should be prepared for the need to evacuate.
Flood-prone roads will see some degree of impact as well as the levels in lakes and rivers rise.
Officials are also warning residents to stay away from large bodies of water and fast-flowing rivers during this time.
According to the MNR, water levels will continue to rise after the rain has stopped falling.
Moose FM will have constant updates on the flood conditions throughout the day.