Season’s First Frost Advisory Issued for Toronto and Southern Ontario: What You Need to Protect and How.

On October 5, 2026, Environment Canada issued a yellow-level frost advisory for Toronto and nearly all southern Ontario. This advisory warns that overnight temperatures may drop near or below freezing and will continue into early tomorrow morning (Tuesday).

Affected Areas:  

The advisory covers most communities along Lake Ontario and the St. Lawrence River, including Kingston and Cornwall. It also includes the Greater Toronto Area and extends as far west as London.

The advisory notes increased vegetation vulnerability to frost in the affected regions, highlighting the risk of damage to plants, trees, and crops from the expected freezing temperatures.

Recommendations:  

Residents are advised to cover cold-sensitive plants and crops to prevent frost damage during the early Tuesday morning chill. The Weather Network indicates that frost is more likely to occur under clear skies and light winds, as these conditions can lead to significant temperature drops.

Fortunately, this cold snap is expected to be short-lived. Much warmer air currently located just south of the border may begin to push into parts of Canada during the Thanksgiving weekend, possibly bringing milder temperatures than initially forecasted. If this occurs, temperatures are expected to rebound to the high teens and low twenties later in the week.

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