Burlington, Ontario, is under an orange heat warning from Environment Canada as a long stretch of dangerously hot weather settles in this week. Daytime highs will climb to 34°C by Wednesday and Thursday, and the humidity will make it feel even hotter, with humidex values reaching 43. The warning took effect Monday, June 29, 2026, and the heat could last through Friday or even into the weekend.
According to Environment Canada, Tuesday will see a high of 33°C with a humidex of 43. The hottest days are expected to be Wednesday, which is Canada Day, and Thursday, when the mercury could hit 37°C in some spots. Overnight lows will hover between 21°C and 25°C, offering little relief after sundown. Normally at this time of year, Burlington sees highs around 26°C and lows around 14°C.
Halton Region Public Health has its own extended heat warning criteria, triggered when temperatures stay at or above 31°C during the day and above 20°C at night for three or more days, or when the humidex reaches 40 for three or more days. This event meets those thresholds, and the medical officer of health is urging residents to take precautions.
Older adults, people living alone, those with chronic health conditions, young children, and infants face the highest risk. Anyone showing signs of heat stroke such as red and hot skin, dizziness, nausea, confusion, or a change in consciousness should get immediate medical help. Residents are asked to check on neighbours and family members who may need a hand finding a cool place to stay.
The City of Burlington and the Burlington Public Library have opened cooling centres at library branches across the city. Public health officials are also warning that hot, humid air can lower air quality, and the Air Quality Health Index may approach the high-risk category during this stretch.
While the air will feel like the mid-40s, Lake Ontario remains chilly. Water temperatures are sitting around 15°C to 16°C, so even a quick dip is likely to be uncomfortable and potentially dangerous for swimmers.
