‘Take cover’: Southern Ontario residents under tornado warning. Live updates here

The Toronto skyline. THE CANADIAN PRESS/Frank Gunn

Residents in several Southern Ontario areas are under a tornado warning Saturday afternoon, as Environment Canada warns some to “take cover immediately in a basement, interior room, or a sturdy shelter when threatening weather approaches.”

Red warnings are in place in Burlington - Oakville, Halton Hills - Milton, Mississauga - Brampton, while several other communities are under severe thunderstorm advisories.

More details to come. Previous coverage continues below...

The City of Toronto is under a “severe” thunderstorm watch and air quality warning as Environment Canada says smoke from wildfires in northwestern Ontario continues to linger and blanket the city.

The national weather agency says wildfire smoke will result in very poor air quality through the morning, with only some improvement possible later in the day.

• Your hourly forecast on our CP24.com weather hub
• Wildfires in Canada coverage on CTVNews.ca

At one point this week, Toronto’s air quality was ranked among the world’s worst, according to IQAir, which prompted outdoor programs and facilities, including pools, to be shuttered.

Today, Toronto is back in the top three, among U.S. cities like New York and Washington D.C.

Key details:

• An air quality warning, yellow alert, remains in effect
• Conditions won’t improve until afternoon, but may worsen tonight.
• Severe thunderstorm, beginning near noon into the afternoon

Follow along for live updates.

11 a.m. - Toronto slides into #2 spot

According to IQAir, Toronto has now slid into second place for the worst air quality in the world, behind only New York City.

The smoky conditions have persisted across the GTA as Environment Canada continues to warn of “poor air quality and reduced visibility due to wildfires.”

10:10 a.m. - Air quality warning now yellow alert

Environment Canada has updated their air quality warning, officially downgrading their alert from Orange to Yellow.

The main difference between an Orange Alert and a Yellow Alert lies in the intensity and duration of the weather event.

9:30 a.m. - Severe thunderstorm watch

Toronto and much of the GTHA is under a severe thunderstorm watch as Environment Canada warns “strong wind gusts” and “heavy rain” is on the way.

The weather agency says thunderstorms are expected to develop beginning around noon and continue through the afternoon as a cold front moves southeast from Michigan.

Officials warn the strongest storms could produce wind gusts of up to 110 km/h, hail ranging from the size of quarters to “ping pong balls” and between 25 and 40 millimetres of rain.

9:15 a.m. - Toronto ranked #1 for world’s worst air

Toronto is back in the top spot for having the world’s worst air leading ahead of New York and Washington D.C.

According to IQAir, the city is ranked in the red “Unhealthy” category, though at one point this week, Toronto was placed in the utmost “Hazardous” category.

9 a.m. - What’s cancelled?

Toronto’s Caribbean Junior Carnival Parade which was set to take place today, has been rescheduled to Sunday, July 19, 2026.

Organizers say the decision was made to due to “inclement weather.”

“The decision has been made with the safety and comfort of the thousands of young participants, their families, volunteers, spectators and event staff as the highest priority,” officials wrote in a statement.

“All event programming will proceed as planned on Sunday, with no changes to the parade route and schedule with only minor changes to some activities to accommodate the date adjustment.”

8 a.m. - Who is at risk?

Officials warn that “everyone’s health is at risk” during periods of heavy smoke, regardless of age or existing health conditions, and are urging residents to limit the amount of time they spend outdoors.

People most vulnerable include seniors, pregnant people, young children, those with chronic illnesses and people who work outdoors. Environment Canada is asking those individuals to avoid outdoor activity and seek medical attention if symptoms develop.

In addition, officials also say some people may experience eye, nose and throat irritation, headaches or a mild cough, while more serious symptoms can include wheezing, chest pain or a severe cough.

The weather agency is advising sports organizations and outdoor event organizers to consider local air quality conditions when planning activities.