Environment Canada has issued a special weather statement for the Greater Toronto Area advising of the possibility of heavy rain followed by snow.
The weather agency said a system is expected to first bring rain as it moves into the region Wednesday night.
The rain will continue into Thursday and “become heavy at times,” with total amounts of 15 to 25 mm possible for much of the GTA, Environment Canada said.
The rain is then expected to switch to snow by Thursday evening or night, potentially leaving some accumulation by Christmas morning.
“There remains considerable uncertainty as to the exact track of this low pressure system and the timing of the changeover from rain to snow,” the statement read.
“This will ultimately affect how much snow may fall at any particular location.”
Environment Canada said drivers should be prepared for poor conditions in areas that receive snow on Christmas Eve and Christmas day.