A special weather statement has been issued for Niagara warning of significant rain.
Environment Canada says remnants from tropical depression Gordon are expected to affect Niagara and much of Southern Ontario beginning Sunday and lasting through till Monday.
Rain is forecast to hit the Golden Horeshoe late in the day on Sunday.
The rain could be heavy at times with total rainfall amounts in the 30 to 60 mm range possible by Tuesday morning.
There is still considerable uncertainty in the timing and track of this weather system.
Rainfall warnings may be required for some areas as the event draws nearer.