‘Dangerous heat and humidity’ rings in summer across Ontario
Posted Jun 21, 2025 11:33:04 AM.
Last Updated Jun 23, 2025 03:15:34 PM.
The summer solstice kicked off the season with a bang as temperatures begin to heat up across southern Ontario including in the Ottawa region.
Environment Canada has issued a heat warning across much of the province. Between Sunday and Tuesday, temperatures as high as 36 C are expected, with the humidex making it feel more like 45 C.
Ottawa is expected to see some showers but the rain will provide little reprieve from the heat. Lows overnight are expected to still peak around 23 C.
It is the first significant heat event of the season, with Environment Canada calling for “dangerously hot and humid conditions.”
The heat will prove especially challenging for those without access to air conditioning in their homes. A report from the tenant advocacy organization ACORN found that 44 per cent of low- to moderate-income tenants lack air conditioning in their units, with affordability cited as the main barrier to access.
The startling statistic has led the organization to call on the city to implement a maximum heat bylaw, but no action has yet to be taken.
There are places in the city that residents can go to cool off, however.
The city has identified a list of over 80 cooling places that include public splash pads and pools, as well as libraries, community centres and parks.
Environment Canada is reminding people to watch for signs of heat exhaustion, especially in young children and the elderly. Signs may include headache, nausea, dizziness, thirst, dark urine and intense fatigue. If you suspect heat exhaustion, halt all activity, drink water and seek a cooler place immediately. If heat exhaustion progresses to heat stroke it can be fatal.
“Never leave people, especially children, or pets inside a parked vehicle,” the warning states. “Check the vehicle before locking to make sure no one is left behind.”