Environment Canada has issued a special weather statement for Toronto and its surrounding regions.
According to the national weather agency, Toronto, Mississauga, Brampton, Belleville, Kingston and the regions of Halton, southern Durham and York are all expected to be affected by the remnants of tropical depression Gordon.
The rain is expected to begin overnight Sunday and continue into Monday.
By the time rain tapers off to scattered showers early Tuesday, Environment Canada says the GTA could receive up to 20-40 mm of rainfall.