What to know about the 'multi-day heat event' in Toronto

Most of Ontario, including Toronto, Mississauga, Hamilton, and Niagara, York, and Durham regions, is under a heat warning as temperatures are forecasted to reach the high 20s to low 30s over the next several days.

Early Tuesday morning, Environment Canada advised people to expect humid, hazy, and hotter-than-usual conditions that could actually feel more like the high 30s to low 40s.

This "multi-day heat event" is expected to last until Thursday.

• Download our app to get local alerts on your device
• Get the latest local updates right to your inbox

David Phillips, a senior climatologist with Environment Canada, said most of Ontario along with many parts of Quebec are currently under a “big, large high pressure area,” which he called “the typical kind of summer weather where we get the Triple Hs: the heat, the haze, and the humidity.”

Hesitant to call it a “dome,” Phillips said heat warnings are being issued from Wawa to Windsor and from Moosonee to Mississauga and across large swaths of the province of Quebec as this latest weather system is stationary in nature.

“So, a lot of millions are actually beginning to feel what summer is typically like, and, and I think in some ways it's kind of the first heat wave of the year,” he said during a Tuesday morning interview with CTV National News, adding what distinguishes this system is the high level humidity it is producing.

“So it's going to feel like jungle humidity: sultry and oppressive. And, and those temperatures always seem a little bit more difficult, hard to handle, and unhealthy when you have that humid air.”

Phillips also noted that previous bouts of high heat across Ontario and Quebec have come with cooler nights, which isn’t the case this time around.

“The nights are going to be warm up 20, 22 degrees. There’s a lot of tossing and turning when you get those kind of conditions. So these are kind of like the dog days of summer and they've started in July and hey, get used to it. I mean, this is summer in Eastern Canada.”

In response to the heat warning, the City of Toronto announced that seven of the city’s outdoor public pools will have their opening hours extended on Tuesday.

Alex Duff, Giovanni Caboto, McGregor Park, Monarch Park, Parkway Forest, Smithfield Park, and Sunnyside pools will all remain open until 11:45 p.m.

“A heat warning does not automatically result in extended pool hours,” the city said in a previous press release.

“Decisions to extend pool hours are made daily while a heat warning is in place, based on weather risks and resource availability. Up-to-date information on extended pool hours, pool locations and regular operating hours is available by calling 311 or visiting the City of Toronto’s website.”

For the time being, Toronto’s other 51 outdoor public pools will continue to operate on their regular schedules.

In its warning, Environment Canada said that while areas near the lakes could be slightly cooler than regions further inland, hot and humid air can still bring deteriorating air quality and can result in the Air Quality Health Index approaching the high risk category.

“Extreme heat affects everyone. The risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors,” the national weather agency said.

People are being advised to keep an eye out for the effects of heat illness, which may include swelling, rash, cramps, fainting, heat exhaustion, heat stroke, and the worsening of some health conditions.

“Drink plenty of water even before you feel thirsty and stay in a cool place. Never leave people or pets inside a parked vehicle,” said Environment Canada, which issues heat warnings when very high temperature or humidity conditions are expected to pose an elevated risk of heat illnesses like heat stroke or heat exhaustion.

“Be a Good Samaritan. Look in on your neighbors and elderly friends who might be a little disorientated under these extreme heat and humid conditions and make sure they're coping,” said Phillips, who also urged people to keep an eye on the weather as thunderstorms often tent to pop up later in the day during especially hot and humid weather systems like the one currently underway.

“And if they don't have air conditioning, well maybe drive them to the mall or to the show and just sort of out to the library and just get them to have a chance to get cooled off.”