Week-long heat wave led to dozens of emergency room visits, Toronto Public Health says

Toronto Public Health says nearly 40 heat-related emergency department visits were recorded during last week’s heat wave that scorched the city.

Officials say Toronto hospitals reported a total of 39 heat-related ER visits from June 30 until July 4, when Environment Canada’s orange level heat alert was in effect.

The highest number was recorded at the peak of the heat wave on July 2, with 15 ER visits.

The health authority says the highest temperature during the heat wave was 36 C, and the highest humidex reading was 48.

It says the trend was similar to the one seen in June 2025, when 42 people landed in emergency rooms over a three-day heat wave. Last week’s heat warning lasted five days.

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Heat dome creates punishing Canada Day conditions

Millions of Canadians spend Canada Day trying to stay cool with temperatures feeling like 40 C in much of Ontario and Quebec because of a heat dome.

Toronto Public Health says emergency room data doesn’t capture all of the health effects linked to extreme heat, such as worsening cardiac and respiratory conditions.

Direct comparisons between ER visits during this heat wave and last June’s are limited because of differences in timing and duration, and the fact that Environment Canada has changed its weather warning system, public health spokesperson Dane Griffiths said in a statement.

Plus, there were expanded heat relief measures this year and Canada Day may have affected the number of people in the city, Griffiths wrote.

The severe heat was cited among the reasons for the cancellation of last Thursday’s World Cup match broadcasts at Toronto’s Nathan Phillips Square. Additional cooling measures were brought in for the final match held at Toronto Stadium that day, and at the flagship FIFA Fan Festival.

Much of the province was under Environment Canada’s orange warning, an uncommon alert that signals severe weather likely to cause significant damage or health effects.