Environment Canada has issued a heat warning for the Greater Toronto Area, saying extreme heat can be expected throughout the region on Friday and into Saturday.
The weather agency said daytime temperatures are expected to reach at least 30 C, but it will feel much hotter than that, with humidex values reaching near 40.
Overnight temperatures are expected to be in the 20s, providing little relief from the heat.
“This is obviously arriving a little later than most summers. We haven’t seen this heat yet, but it’s still a shock to the system,” Global News meteorologist Anthony Farnell said.
This is the first heat warning of the year for the GTA.
Everyone is encouraged to drink plenty of water and stay in a cool place during the extreme temperatures.
“If you have any activities this afternoon, you may want to consider shortening that or perhaps cancelling altogether,” Farnell said.
Environment Canada said young children, older adults, pregnant women, people with chronic illnesses and people who work outdoors are especially at risk of health effects due to the heat.
In Toronto, there are over 270 cool locations throughout the city where residents can go to get some relief, including community centres, civic centres, pools, and several private and non-profit organizations.
In May, changes to the way the City of Toronto issues heat warnings took effect. The city no longer issues its own heat alerts and now follows the advice of Environment Canada.
The city is reiterating the weather agency’s message, encouraging residents to drink plenty of water and remain in cool locations throughout the warning.
With the intense heat and humidity also comes the chance for thunderstorms.
“With all of this, we are going to see some showers and thunderstorms bubbling up,” Farnell said.
Scattered storms could cause heavy rain at times throughout southern Ontario on Friday and some of Saturday, he said.
More comfortable weather is expected to move into the region on Sunday.
WATCH: Health Matters: Signs and symptoms of heat stroke