Heat wave blamed for 42 Toronto emergency room visits, public health says

The sun rises over the Toronto skyline bringing with it another day of high temperatures on Tuesday June 24, 2025. THE CANADIAN PRESS/Frank Gunn

TORONTO — Toronto Public Health says it recorded 42 heat-related emergency department visits during the heat wave that gripped much of Ontario earlier this week.

The heat wave delivered dangerously high temperatures and humidity to many parts of southwestern Ontario, with Toronto setting a new June 23 temperature record when the mercury hit 36 C.

A public health spokesperson says the number of weather-related ER visits to Toronto hospitals over the three-day heat wave is consistent with the health risks of heat exposure, “particularly for vulnerable populations.”

Toronto Paramedic Services say they saw a “slight increase” in overall call volume from Sunday to Tuesday, but they are unable to track how many calls are directly related to heat even though it may be a contributing factor.

Ottawa also set a new June 23 heat record when the temperature there topped out at over 35 C.

Ottawa Paramedic Service said on Wednesday that it had responded to 14 calls directly related to heat since Saturday, with all but one patients in stable condition.

They say an elderly man with dementia was found in a backyard suffering from heat stroke on Monday, and was stabilized before he was taken to hospital in critical condition.

The Office of the Chief Coroner didn’t have information about any recent heat-related deaths in the province, saying they are difficult to track accurately.

“It is very challenging to determine with accuracy whether heat was a direct factor in causing a death,” spokesperson Stephanie Rea said in an email. “In many cases, a person may present to a hospital for a pre-existing condition exacerbated by the heat.”

Rea said only accidental deaths that are directly related to heat, such as hyperthermia or dehydration, are reported to the coroner for investigation.

While the heat warning officially lifted Wednesday in many parts of the province, relief is expected to be short-lived as Environment Canada forecasts temperatures will climb again to the high 20s starting Friday for parts of southwestern Ontario.

This report by The Canadian Press was first published June 26, 2025.

Natasha Baldin, The Canadian Press