Montreal under severe thunderstorm watch Monday
Posted August 10, 2026 7:47 am.
Last Updated August 10, 2026 1:02 pm.
Environment and Climate Canada (ECCC) issued an alert Monday morning to warn the public that severe thunderstorms, and possibly even tornadoes, are expected across much of southern Quebec starting around midday.
The federal agency stated that it has assessed the impact level as “moderate,” with “high” confidence in its forecast.
The regions specifically targeted by this alert are the Outaouais, the Laurentians, Lanaudière, and Greater Montreal.
“There could be more severe thunderstorms in these regions, with significant amounts of rain. We’re talking about 40–50 millimetres that can fall very quickly, so we can expect sewer backups and urban flooding. Strong winds could also affect these areas, so broken branches and power outages could follow later in the day,” says Simon Legault, a meteorologist with ECCC.
“There’s also a risk of tornadoes. Some thunderstorms could generate tornadoes, but we can’t pinpoint the locations or the strength of these tornadoes. Hail could also fall, possibly 2 to 4 centimetres in size—about the size of a 25-cent coin or a $2 bill,” he adds.
There is also a risk of less severe thunderstorms in the Québec City region, Abitibi, Mauricie, and Estrie throughout the day and into the evening.
Forecast
Monday will be mainly cloudy with a chance of showers and thunderstorm starting this afternoon. A daytime high of 26 Celsius and a low of 19 C.
Tuesday is expected to have a mix of sun and cloud and a high of 26 C and clear nights with a low of 16 C.
Wednesday will be sunny with a high of 26 C with some cloud cover overnight for a low of 17 C.
Some wet weather is possible again Thursday with a 60 per cent of showers and a high of 23 C and a low of 14 C.
Montrealers can expect nice weather to end the week and going into the weekend with Friday forecast to be sunny with a high of 23 C and clear nights and a low of 12 C.
— With files from The Canadian Press
