It couldn't come at a worse time.

As thousands of residents plan holiday trips this weekend, Environment Canada has issued a Freezing Rain Warning for freezing rain warning for: London-Middlesex, Sarnia-Lambton, Elgin, Oxford, Huron, Perth, southern Grey and Bruce as well as most of the GTA.

A major ice storm will likely start Saturday afternoon and continue into the evening and Sunday morning.

A significant frontal boundary from Sarnia to Hamilton eastwards across Lake Ontario is expected to remain in the area for the next couple of days.

North of this front, periods of freezing rain will taper off or change to drizzle or freezing drizzle Saturday morning.

Regions from southern Lake Huron to Toronto are expected to see temperatures rise just above the freezing mark.

The next disturbance is over Texas and will track towards the lower Great Lakes Saturday evening.

Freezing rain may be heavy at times, with 20 to 30 mm of freezing rain possible.

As a result, ice accumulation on trees and power lines could potentially create widespread power outages and downed trees.

Driving conditions on untreated roads could become very hazardous.

Motorists and pedestrians should exercise caution and adjust travel plans accordingly.

Meanwhile, it's a different story for those in the extreme southwest of the province, as Windsor-Essex and Chatham-Kent are under a Rainfall Warning.

Those areas could see anywhere from 25 to 35 mm of rain Saturday.

Temperatures are expected to remain just above 0 degrees.