Kingston, Ontario is under a multi-day heat warning as Environment Canada forecasts a prolonged stretch of very hot conditions from June 29 through July 3, 2026. Temperatures are expected to climb well above the seasonal normal of 25°C, with highs reaching 32°C or 33°C by mid-week, and overnight lows barely dipping below 20°C. The warning means residents should brace for days of intense heat and humidity that could pose health risks, particularly for those living alone or without access to cool spaces.
According to Environment Canada, the mercury will hit 29°C on Tuesday with a humidex of 38, before climbing to 32°C on Wednesday, 32°C on Thursday, and 33°C on Friday. Overnight lows will hover between 18°C and 22°C, offering little relief from the daytime highs. There is a 30 to 40 percent chance of showers and a risk of thunderstorms through the period, but the overall pattern remains hot and muggy. The UV index is forecast to be high, reaching 7 on Tuesday, so sunscreen and hydration are essential for anyone spending time outdoors.
KFL&A Public Health has also issued a concurrent heat warning, cautioning that the combination of heat and humidity can lead to dehydration and heat-related illnesses. These include heat stroke, heat exhaustion, heat fainting, heat edema, heat rash, and heat cramps. People most at risk are infants and young children, pregnant individuals, older adults, people who live alone, those with chronic medical conditions or mental illnesses, people experiencing homelessness, and outdoor workers. Officials are urging everyone to check on vulnerable family members, friends, and neighbours during the heat wave.
To help residents cope, the City of Kingston has designated several cooling locations where anyone can go to escape the heat. These include the INVISTA Centre at 1350 Gardiners Road, the Central Library Branch at 130 Johnson Street, the Calvin Park Library Branch at 88 Wright Crescent, the Cataraqui Centre at 945 Gardiners Road, the Kingston East Community Centre at 779 Highway 15, and Housing and Social Services at 362 Montreal Street. The city also approved a $17,000 Residential Air Conditioner Assistance Pilot Program in April 2026 to help older residents stay cool during extreme heat events.
The heat wave coincides with Canada Day festivities, when many residents will be gathering outdoors. Environment Canada advises seeking shade, wearing a hat and loose-fitting clothing, and drinking plenty of water throughout the day. The hottest conditions are expected through Friday, with temperatures gradually moderating over the weekend but remaining above seasonal norms.
