Southern Ontario: Fall Weather Hazards Outlook for Friday, October 29, 2021

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Forecast Discussion

Heavy rain will start to move into regions along the Lake Erie shoreline early Friday and continue throughout the day. Other parts of Southern Ontario including areas around GTA and into Eastern Ontario will also see some rain later in the day and into Saturday morning, but it’s not expected to be as intense. Rainfall totals between 20-40mm are expected from the Hamilton/Niagara region to Extreme Southwestern Ontario (Windsor, Chatham etc.).

The bulk of the rain will fall on Friday but around 5-10mm may come overnight into Saturday morning with higher amounts on Saturday for Eastern Ontario. Rainfall totals between Friday and Saturday may exceed 25mm around the GTA and the Lake Ontario shoreline although 25+mm isn’t expected on one day so that’s not included on the map. Other areas can expect 5-10mm with lower amounts the further north and west you go.

In addition to the rainfall, there is the risk of frost for parts of Eastern Ontario on Friday morning. Temperatures are expected to come near the freezing mark which may allow for some frost to develop particularly in higher elevations around Bancroft and Algonquin Park.

Southern Ontario: Fall Weather Hazards Outlook for Sunday, October 24, 2021

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Forecast Discussion

Temperatures are expected to drop to near the freezing mark throughout much of Southern Ontario during the morning on Sunday. This will bring the risk of frost to all areas away from the shorelines of Lake Ontario, Erie, Huron and Georgian Bay. Be sure to protect any sensitive plants that you want to save. The frost will melt away later in the morning after the sunrise.

Southern Ontario: Fall Weather Hazards Outlook for Saturday, October 23, 2021

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Forecast Discussion

Near-freezing temperatures will once again be found across parts of Central and Eastern Ontario on Saturday morning. This will bring the risk of frost to the area so you should cover up and protect any sensitive plants that you want to save. In addition to the frost risk, we also could see some lake effect precipitation around Georgian Bay and into Northeastern Ontario and with the colder temperatures, it may come down in the form of flurries or wet snow. The confidence is low on this as any precipitation will be very scattered and weak so not anyone will see it and there will be little to no accumulation due to the ground still being relatively warm. Temperatures will rise later in the morning which will melt away any frost and turn any flurries over to rain showers.