Umbrellas out: Stormy, soggy weekend ahead for much of Ontario

Ontario's unsettled weekend could bring hail, gusty storms and widespread soaking rains

A sneaky thunderstorm threat is forming across parts of Ontario on Saturday as a cold front approaches the Great Lakes. This isn't the typical midsummer setup, fueled by extreme heat and humidity. 

Forecasters are instead looking at a "high-shear, low-CAPE" environment, which has limited storm energy but stronger winds aloft that are capable of helping storms organize.

A few thunderstorms with strong winds and large hail cannot be ruled out.

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Ontario and Quebec Saturday severe thunderstorm risk - June 13, 2026

Quiet setup with notable impacts

Storms are projected to develop Saturday afternoon in northeastern Ontario, including near Sudbury, before moving east toward North Bay and south toward Lake Simcoe and Peterborough around dinnertime.

A widespread severe weather threat does exist across the region, including cottage country, where changes in wind speeds and directions with height may cause some storms to rotate briefly. The primary threats, however, will be strong winds, large hail and heavy downpours.

Ontario Saturday evening forecast storms - June 13, 2026

The thunderstorm risk is expected to persist into Saturday evening in eastern Ontario.

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Sunday turns soggy

The unsettled pattern continues into Sunday, as the same slow-moving frontal system stalls across southern Ontario. Rounds of thunderstorms capable of producing heavy downpours are expected, with some areas receiving more than 30 millimetres.

Storms may move through the Greater Toronto Area (GTA) and southwestern Ontario between 10 a.m. and 2 p.m. ET, with minor effects. Flash flooding and pooling water on roads and in low-lying areas are possible where the most rain falls.

Ontario Sunday afternoon forecast storms - June 13, 2026

Those who have weekend plans should keep an eye on the sky on Saturday. By Sunday, an umbrella might be the better accessory.

Behind the cold front, folks will feel a noticeable temperature drop across the province, with temperatures dipping to slightly below seasonal on Monday.

Stay with The Weather Network for the latest across Ontario.