Toronto bakes under the first heat wave of the summer. Here’s how long it will last.

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CP24 LIVE: Toronto's Breaking News

CTV National News: Millions of Canadians under extreme heat warnings

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How Canadians can stay safe from sweltering temperatures

It’s going to be a hot and steamy week in Toronto and much of Ontario as the first heat wave of the summer sets in, starting today.

The Greater Toronto Area and much of the province are currently under heat warnings from Environment Canada.

According to the orange warning issued by the national weather agency for Toronto, temperatures could reach as high as 37 C from Tuesday through Friday, possibly stretching into the weekend as well. Humidex values will make it feel like 43 on Tuesday and 44 on Wednesday.

At the same time, minimum temperatures of 21 to 25 C are expected to provide little overnight relief from the sweltering temperatures.

Our live coverage has ended. To stay up to date on the latest forecast information, tune in to CTV News Toronto and CP24. 

Scorching end to June, Canada Day forecast

The last day of June was a scorcher in Toronto, and it is just day one in what is set to be a long-duration heat wave.

The city reached 34 C this afternoon, feeling like 44 with the humidity. At one point, Pearson Airport was the hot spot of the country. The record to beat today was 35°C. 

Toronto remains under an orange-level Heat Warning, and one reason for its severity is that temperatures remain uncomfortably warm at night. Any time lows remain above 20 C, it can be difficult for body temperatures to regulate and cool down.

Tonight’s forecast low is 23 C, which is close to 26°C - the average daytime high this time of year.

July will get off to a sweltering start on Wednesday, too. We’re forecasting a high of 35, with a humidex of 45.

We have had some hot Canada Days here in Toronto over the last 25 years, including in 2012 and 2018. The hottest in recent years was Canada Day 2002, when the temperature climbed to 35.6 C, and we could rival that tomorrow.

There is also a risk of thunderstorms on July 1 in the late afternoon and early evening. Keep this in mind if you will be out enjoying Canada Day festivities. Conditions should be clear in time for fireworks in the late evening.

Lyndsay Morrison, CTV News Toronto weather anchor

Daytime high reached

It appears Toronto reached its daytime high of 34.2 C at 3 p.m. as according to new data from Environment Canada, the temperature dropped to 32.8 C at 4 p.m. with a humidex of 42.

There won’t be much of a reprieve anytime soon as the temperature is only expected to dip to a low of 23 C.

Toronto is Canada’s hot spot

As of 3:00 p.m., Toronto Pearson airport is the hot spot of Ontario and Canada at 34.2 C with a humidex value of 44.

That means that no other town or city has hit a temperature higher than Toronto so far today.

The record to beat today is 35.0 degrees, set back in 1964.

Lyndsay Morrison, CTV News Toronto weather anchor

People doing what they can to beat the heat

Despite the heat, some workers and active residents say they are staying outdoors today.

CTV’s Beth Macdonell spoke with one construction worker who says he’s staying cool by drinking lots of water.

Some pickle ball enthusiasts weren’t willing to skip their game, but got going earlier to avoid the hottest part of the day.

CP24.com Staff

Toronto temperature soars above 30 C

According to Environment Canada, the temperature in Toronto continues to climb this afternoon, reaching 30.9 C with a humidex of 42 at Pearson International Airport at 1 p.m.

The temperature at the airport soared to 33 C with a humidex of 44 an hour later.

Bryann Aguilar, CP24.com journalist

Hottest Canada Days in Toronto

This Canada Day in Toronto will likely be one of the hottest the city has experienced in recent years. Right now, the record temperature is the one set on July 1, 2002, when Pearson airport recorded a high of 35.6 C with a humidex of 44.

Right now, we are forecasting a high of 34 degrees for Wednesday, July 1, 2026, but it will be feeling closer to 44.

Other sweltering Canada Days happened in 2012 and 2018, when Toronto temperatures climbed to highs of 31.3 C and 34.3 C, respectively.

A reminder to take care of yourself and others if you are heading to any festivities by staying hydrated and taking regular breaks in a cool area. There is also a risk of thunderstorms in the afternoon and evening ahead of fireworks displays, so be sure to keep an eye on the sky.

Lyndsay Morrison, CTV News Toronto weather anchor

Heat wave with a chance of GO Train delays

Metrolinx says there are potential impacts to GO Train service due to the hot weather.

“During prolonged periods of high heat, we are required to run trains at slower speeds. To ensure the safety of our customers and crew, slow orders are issued along the network,” the Crown agency said in a statement on Tuesday.

“As a result, some trips may be cancelled or delayed on your line today arriving 10 to 15 minutes later than originally scheduled at their destination.”

In a video on its YouTube channel, GO Transit explains that railway tracks in direct sunlight could heat up and become extremely hot, causing them to expand and potentially buckle, which is called a “sun kink.”

The agency said if a track buckles, it becomes wider than normal, resulting in problems for trains.

Slowing down the trains, GO Transit says, will reduce the impact of expanded rails and lower the chance of a sun kink.

Bryann Aguilar, CP24.com journalist

Toronto top doc’s advice on beating heat

Dr. Michelle Murti, the city’s medical officer of health, is asking residents to check on their elderly neighbours this week, especially those who are living alone and who may not have access to air conditioning.

“Let’s be good Canadians, let’s check in on our neighbours, let’s check in on people who live around us,” Murti said in an interview on Tuesday with CP24.

The city issued a heat alert on Monday, which activates services to help residents cool off. Murti said pools and splash pads are operating on extended hours.

“That cool water is one of the most effective ways to really bring down your core temperature if you’ve been too hot,” the doctor said.

She noted that there are also 500 cooling spaces available across the city as well as hydration stations.

Looking ahead to Thursday’s World Cup match, Murti said there will be extra water trucks and misting tents at the stadium and the FIFA Fan Festival.

“I really encourage people to take advantage of some of the shaded areas. We do have a cooling area within Fort York as well, where people can get a little bit of air conditioning relief,” she said.

Murti noted that it is important to pay attention to symptoms of dehydration or overheating, which include headache, nausea and dizziness.

“If you see somebody who’s really doing unwell, looking confused, very dizzy, very nauseous, they may even pass out, those are real signs of heat emergency that you need to be calling 911 or getting help if you see somebody in that condition,” she said.

Bryann Aguilar, CP24.com journalist

Peel Public Health issues heat warning

Peel Public Health has issued a heat warning for Peel Region as hot temperatures and humidity set in for several days.

Medical Officer of Health Dr. Alexa Caturay urged people to be mindful of how the hot weather can affect health in the coming days.

“With many residents planning to spend time outdoors celebrating Canada Day and enjoying summer activities, it’s important to remember that extreme heat can quickly become dangerous,” Caturay said.

“Heat-related illnesses are preventable. We encourage everyone to drink water frequently, take breaks in cool or shaded areas, and check in on older adults, young children, neighbours, those with chronic illness and others who may be more vulnerable to the effects of extreme heat.”

People at higher risk of experiencing heat-related illness include older adults, infants and young children, individuals with chronic illness, and people who work outdoors.

Information on local cooling centres can be found on each municipality’s website.

Joshua Freeman, CP24 journalist

Ontario air conditioning law coming into effect

An Ontario law giving tenants the explicit right to install air conditioning units is set to come into effect Wednesday, in the midst of a stifling heat wave.

The section of a 2023 law will be in force as of July 1 and allows tenants to install and use a window air conditioner or portable unit if their landlord doesn’t supply air conditioning, subject to certain conditions.

Read more here.

The Canadian Press

Risk of storms almost every day

Because the excessive heat and humidity act as potential energy and fuel for the development of storms, there is the risk almost every day through Saturday of seeing local showers or storms.

This morning, we’ll likely see some active weather on the east side of the GTA. Wednesday could bring some strong storms in the afternoon and evening. Thursday may bring isolated pop-up p.m. showers.

Friday could see a few showers. And there will remain the risk of a few showers or storms on Saturday. Humidity finally falls for Sunday and Monday. But it will remain very warm. Variable skies for Sunday. Bright sunshine for Monday.

Bill Coulter, CP24 meteorologist

Canada Day will be one of the hottest days

According to Environment Canada, the peak of the hottest days this week are expected to be Wednesday and Thursday, with maximum temperatures of 34 to 37 C expected. That means those heading out for Canada Day activities will need to be prepared for the sweltering temperatures.

Environment Canada warned that the hot, humid weather can also lead to deteriorating air quality.

“Check on older adults, those living alone and other at-risk people in-person or on the phone multiple times a day,” the weather agency advises. “Watch for the early signs of heat exhaustion in yourself and others. Signs may include headache, nausea, dizziness, thirst, dark urine and intense fatigue.”

People are being advised to avoid strenuous activities outdoors and to drink plenty of water to stay hydrated.

Joshua Freeman, CP24 journalist

Toronto’s final FIFA match set for Thursday

The final FIFA World Cup match to be played in Toronto is scheduled for 7 p.m. Thursday amidst the heat wave.

The Round of 32 knockout game will see Portugal take on Croatia at Toronto Stadium (BMO Field), with FIFA Fan Festival Toronto happening at Fort York and The Bentway from 1:30-10:30 p.m. that day.

FIFA officials encourage game-goers to drink water before, during and after matches — at least one cup (250 ml) every 20 minutes in hot conditions. Fans can bring one soft plastic 20-ounce (590 ml) factory-sealed disposable water bottle into Toronto Stadium, officials say, but hard-sided bottles are not allowed.

Prior to the games, FIFA shared its last-minute plan to prohibit fans from bringing their own water bottles into venues. The association then tweaked this policy, following backlash, to allow one disposable water bottle per person.

Toronto Mayor Olivia Chow called the ban “a pure money grab,” while the city’s medical health officer had also expressed concern about the policy.

“If there was a heat alert on a game day, and people didn’t have access to water, we are concerned about the potential for heat impacts,” Dr. Michelle Murti said.

Meanwhile, at Fan Fest, one reusable water bottle is allowed per guest. It must be empty, plastic (not metal or glass) and a maximum size of 34 ounces (1 litre).

The City of Toronto says extra mobile drinking water trailers will be available on game day at 34 Hanna Ave., Fort York Boulevard and Bathurst Street, and Inukshuk Park.

There are also cooling spaces across the city, with more information here.

Ethan Morneau, CTVNews.ca national digital producer

Much of Ontario under advisories

The heat warnings from Environment Canada affect much of the province, stretching from Windsor to Peterborough east-west, and into northern Ontario.

Areas under the orange warning include the Greater Toronto Area (GTA), as well as London, Kitchener-Waterloo, Barrie and Collingwood.

A patchwork of yellow warnings are in place around the province as well, including cottage country, Sudbury, Sault Ste. Marie and Thunder Bay.

Joshua Freeman, CP24 journalist