Heat alert issued for Toronto

A heat alert has been issued for the city of Toronto as temperatures are expected to soar past 30 degrees today.

Toronto’s Medical Officer of Health issued the alert Saturday morning.

The city advises residents to drink plenty of water, avoid going outside during peak sun hours, wear loose clothing and limit physical activities.

Along with the heat alert is a humidex advisory issued by Environment Canada for Toronto and the rest of southern Ontario.

The hot and hazy conditions are expected to continue through the weekend. Most of the region will be hit with daytime high temperatures in the 30 C to 35 C range on Sunday, with the humidex making it feel as warm as 42 C.

It’ll even be hard to sleep before heading back to work Monday, with humidex values above 30 C on Sunday night.

On Monday, residents will get a break as a weak cold front moves in over most of southern Ontario. However, Environment Canada warns the muggy weather will return by mid-week and continue into the next weekend.

Despite the sweltering weather, the city’s cooling centres do not open for heart alerts. The seven locations are available during extreme heat alerts, defined as days when weather conditions suggest that the likelihood of heat-related death is at least 50 per cent greater than on a typical day.

A heat alert indicates weather conditions suggest the chance of death stands at 25 to 50 per cent greater than on a typical day, according to the Toronto Public Health website.

Instead, Torontonians can cool off at air-conditioned public places, including community centres and libraries.

The city has issued two other heat alerts this year, on May 31 and June 8.

Surprisingly, hot weather isn’t the only consideration when the city issues a heat alert.

George Matsumura, a spokesperson for Toronto Public Health, said Wednesday that a number of factors, including wind speed, dew point, humidity and cloud cover, and the number of consecutive hot days need to be evaluated.

Just because it’s 39 C outside doesn’t mean an alert will be issued. If it’s 39C, there’s no wind, and there is a “humid, moist, tropical air mass,” though, it is likely that there will be an official alert.

“It’s not a simple thing,” he said.

Matsumura said the key factor in a heat alert is mortality. When it’s difficult to breathe outside due to heat and humidity, older people and small children, as well as others with health concerns like diabetes, can be in serious danger.

Environment Canada recommends drinking lots of water of juice to stay hydrated when it’s hot and humid. The agency also suggests wearing loose-fitting, lightweight clothing and scheduling outdoor activities for the early morning or evening.

- Aleysha Haniff and Amanda Kwan, with files from Sarah Ratchford.