Environment Canada says freezing rain is expected in the Guelph area and Waterloo region on Friday.
The agency said precipitation forecast to move through southern Ontario early Friday morning is likely to fall as freezing rain.
It could last for several hours before the temperature rises above the freezing mark.
The weather office said ice build-up is likely and untreated surfaces such as roads, walkways and parking lots may be slippery.
Environment Canada is expecting a high of 5 C on Friday.
Mother Nature should make up for it on Saturday with a forecast of sunny and a high of 13 C.