The Weather Network has issued a warning for a severe storm threat across southern Ontario, including the Greater Toronto Area, on Thursday, July 9, 2026. The storm is expected to bring heavy rainfall of 30 to 50 mm, large hail, strong winds, and a high humidex making it feel like 36°C.
Storm Timing and Hazards
“A strong system is set to affect Ontario through Thursday, delivering widespread risks of severe thunderstorms,” The Weather Network reported. “The primary hazards associated with these storms are heavy rain, large hail, and potentially damaging winds. Residents are urged to remain vigilant as conditions evolve.”
The forecaster indicates that by early afternoon, instability behind the warm front will increase thunderstorm energy, with severe storms moving inland and impacting the GTA as early as 1–2 p.m. ET.
Driven by Muggy Air Mass
The storm is fueled by a muggy and humid air mass ahead of a system approaching the Great Lakes. Humidex values are expected to climb into the mid-30s, with abundant moisture available to intensify storm activity. The high temperature is forecast to be 28°C, but the humidex will make it feel like 36°C.
Impact on Travel and Infrastructure
“Slowdowns are possible along major highways, including the 400, 404, and 401, due to heavy rain,” The Weather Network warned. “Localized rainfall amounts of 30-50 mm are possible under thunderstorms, along with strong gusts and hail up to toonie size.”
By late afternoon and evening, thunderstorms are expected in southwestern Ontario along the system’s cold front, with large hail, strong winds, and heavy rain as the main threats as storms progress.
Outlook for Friday and Weekend
On Friday, the humidex will remain in the 30s°C across parts of Ontario, with the chance of pop-up, isolated thunderstorms. Conditions are set to become more seasonal heading into the weekend. This storm follows a week-long heatwave in Toronto from June 30 to July 4.
