Toronto gets brief relief but no long-term shelter from extreme heat

July 6, 2018

The heat warning that was in effect for the past week across the GTA was lifted Friday, as temperatures in the region return to seasonal averages.

But Torontonians should get used to sweating through more days of extreme heat, according to a senior climatologist.

“The trends have shown us that we are living in warmer times and all indications are that this kind of trend is going to continue,” David Phillips, senior climatologist with Environment Canada, told CBC Radio’s Metro Morning.

Phillips recently analyzed weather trends over the past 100 years and pointed to increasing numbers of “tropical” nights and days above 30 C as indications that sweltering days will likely be a common feature of Toronto’s future weather.

“Clearly what we’re seeing is what Torontonians didn’t have to deal with 100 years ago,” said Phillips.

Phillips defines a tropical night as one during which temperatures remain 20 C. Toronto has seen four instances in the past week with nighttime temperatures above 20 C, he said, which is more than the total yearly average from 100 years ago.

A similar trend emerges for days with temperatures over 30 C. The average number of days above 30 C a century ago was seven. This year, Toronto has seen 20 such days already, said Phillips, with maximum temperature recordings inching increasingly higher.

In response to the sustained heat, the city opened seven cooling stations in local community centres across the city and extended hours at public swimming pools.

Temperatures this weekend are expected to return to more comfortable levels, said Phillips.

According to Environment Canada, Toronto will see a daytime high on Friday of 25 C, though it will feel more like 28. The Saturday high is expected to be 26 C and Sunday is forecast to be 29 C.

Phillips said the heat wave is a harbinger of what’s to come in July and August, so Ontarians should get used to the warmer weather.

“The summer we’re going to get, very unlike last year, which was cool and wet, this one’s going to be dry and hot,” he said.