Toronto issued an extreme heat alert on Monday, as Mother Nature delivered a dose of hot, sticky weather that typically comes later in the summer.

When are heat alerts issued?

Toronto's medical officer issues a heat alert when "forecast weather conditions suggest the likelihood of a high level of mortality is between 25 and 50 per cent greater than what would be expected on a typical day," according to the City of Toronto website.

And an extreme heat alert? Those are issued when "forecast weather conditions suggest that the likelihood of a high level of mortality is at least 50 per cent greater than what would be expected on a typical day."

Before announcing a heat alert, the city takes into account weather conditions such as temperature, dew point, humidity, cloud cover, and wind speed and direction.

Source: City of Toronto

"What we are seeing right now is almost what you would see in the dog days of summer," said David Phillips, senior climatologist at Environment Canada.

The temperature hit an afternoon high of 32 C at Toronto’s Pearson International Airport, though the humidex made it feel more like 40.

For residents of a downtown condo building near Yonge and Harbour streets, the hot weather coincided with a power outage that left them waiting for the air conditioning to be restored.

Joel Cruz spent the day outside his 11th floor unit, where it was simply too warm to stay.

"Although we have windows and a door to the balcony, we’re not getting a lot of wind going up there, so it’s really sticky," Cruz told CBC News.

The extreme heat alert was an upgrade to the existing heat alert that was declared the day before.

During an extreme heat alert, people are encouraged to check on family, friends and neighbours, especially vulnerable adults and children, to make sure they are keeping cool and drinking plenty of fluids.

People are also encouraged to seek shelter at air-conditioned shopping malls, libraries, community centres and city-run cooling centres.

Other tips on coping with the heat include drinking lots of cool water, wearing loose, breathable clothing and a hat, staying in the shade and never leaving children, seniors or pets unattended in a car.

With a report from the CBC's Shannon Martin and files from The Canadian Press