During the recent heat wave in Toronto, the city’s emergency departments experienced a surge in visits, with nearly 40 cases directly linked to the extreme temperatures. Toronto Public Health reported that between June 30 and July 4, hospitals recorded a total of 39 heat-related visits during the period when an orange level heat alert was in effect. The peak of the heat wave on July 2 saw the highest number of emergency room visits at 15.
The highest temperature recorded during the heat wave was 36 degrees Celsius, with a humidex reading reaching 48. However, it was noted that the actual impact of the extreme heat on health could be more extensive than what is captured by emergency room data, especially concerning conditions like cardiac and respiratory issues exacerbated by the heat.
Dr. Edward Xie, an emergency physician at the University Health Network, mentioned that his hospital experienced higher patient volumes last week, although attributing this solely to the heat is challenging. He emphasized the complexity of distinguishing between heat-related illnesses and those where heat worsens existing health conditions.
Comparing the recent heat wave to a similar event in June 2025, Toronto Public Health highlighted that the duration of last week’s heat warning was longer, spanning five days. However, making direct comparisons between the number of ER visits in the two instances is complicated due to timing differences and changes in Environment Canada’s weather warning system.
Xie stressed the importance of addressing climate change through policy interventions rather than relying solely on individual preparedness to combat the effects of extreme heat. He underscored that air conditioning cannot be the ultimate solution, as it leaves communities vulnerable to power outages.
The increasing severity and duration of heat waves globally are attributed to climate change driven by the burning of fossil fuels. Xie recommended preventive measures during heat waves, such as staying hydrated by consuming cool fluids and avoiding dehydrating beverages like alcohol and sugary drinks. Additionally, he cautioned that fans may not provide relief in very hot rooms, emphasizing the need for proactive planning and awareness of heat wave risks.
The recent heat wave coincided with outdoor gatherings for Canada Day and World Cup events in Toronto, leading to the implementation of additional cooling measures due to the extreme heat. Much of the province was under an orange warning from Environment Canada, signaling the potential for severe weather and associated health risks.