Your weather when it really mattersTM


Please choose your default site


Asia - Pacific


Humidity on the rise in Ontario, brings threat of storms

Sunday, August 9th 2020, 7:00 am - Ontario's heat and humidity are on the rise. Chance of storms for the north-west and pop-up showers for southern areas of the province.

The heat continues to rise Sunday and into Monday for Ontario. North-western Ontario may have some rain as energy comes in from the Prairies. Chance of pop-up showers in southern Ontario as well as the heat and humidity rise. The week will be a lot hotter too. Humidex values will be approaching or at 40 Monday. Details and timing, below.


  • Risk of storms for north-western Ontario on Sunday
  • Pop-up storms for southern Ontario on Sunday
  • Heat, humidity on the rise, with temperatures in the 30s Monday
  • Keep an eye on weather ALERTS in your area


A round of storms are expected to reach southern Ontario including the GTA early Sunday morning. Meanwhile, northern-western areas may see severe storms during this time. With expected clearing in the south in the afternoon, there could be enough daytime heating and lake breeze convergence to spark pop-up storms in the late afternoon, early evening hours.

ON Rain Sun-Tues

Areas at risk extend from the Niagara region to eastern Ontario. Some of the storms may become severe, with threats of small hail, strong wind gusts and heavy rainfall. The storms will occur ahead of a front, which will sweep through in the overnight hours.

Sunday ON

Temperatures will be slightly warmer, and will be just above seasonal, with more humidity, as well. Daytime highs will inch ever so closer to the 30-degree mark in the south, and even topping that mark in the southwest. Humidex values will be in the mid- to upper-30s across most of the region.

On Monday, a similar setup will unfold, with a hot and humid airmass in place in southern Ontario. With enough instability, non-severe thunderstorms could fire up in the afternoon through the overnight period.

Daytime highs will hit the 30s in most locales in the south, with humidex values in the upper-30s, close to 40, even hitting 40 in some spots in the southwest.

Mon ON

On Tuesday, temperatures won't stray too far from Monday's, though with slightly less humidity, which will decrease further by mid-week, along with temperatures dipping below 30°C.

Check back as we continue to monitor the forecast.

Default saved

Search Location


Sign In

Please sign in to use this feature.