Environment Canada has issued a special weather statement for a good portion of southern Ontario, stretching from the London area all the way to Peterborough and Belleville.
The agency has also issued a rainfall warning for the southern tip of the province including Sarnia, Chatham and Windsor.
READ MORE: Current weather conditions in Toronto
The special weather statement says those areas will see 15 to 30 millimetres of rain on Monday before it tapers off in the evening. Some areas could experience rainfall amounts of 30 to 50 mm.
The warning for the southern tip of the province says some areas could see 15 to 25 mm on Monday with total rainfall amounts of 40 to 60 mm.
The rain is expected to taper off this afternoon in the Windsor-Sarnia-Chatham neck of the woods.
Environment Canada warns that some areas could see localized flooding and suggests clearing storm drains of leaves and debris, when safely possible, to prevent flooding.
The agency says the heavy rains are courtesy of a low-pressure system that is expected to travel northeast across a southern portion of the province on Monday.