The first significant heat event of the season is bringing dangerously hot and humid conditions to the region, with the oppressive weather expected to continue through Tuesday night.
Environment Canada is forecasting daytime highs ranging from 33 to 36 C, with humidex values pushing temperatures to feel more like 42 to 46. Overnight lows between 22 and 25 C will offer little relief from the heat.
Residents are urged to take precautions to protect themselves and others, particularly vulnerable populations such as older adults and people living alone.
Health officials advise watching for early signs of heat exhaustion — including headache, nausea, dizziness, intense fatigue, thirst and dark urine — and to drink water and stop activity if symptoms occur.
Heat stroke is a medical emergency. Call 911 if someone exhibits symptoms such as red, hot skin, confusion, nausea, or a change in consciousness. While waiting for help, try to cool the person by moving them to a shaded or air-conditioned place and applying cold water or ice packs.
People are advised to drink water often, keep living spaces cool with fans or air conditioning, or seek cooler public spaces like libraries, malls or community centres. Outdoor activities should be scheduled for the coolest parts of the day, and light, loose-fitting clothing with sun protection is recommended.
Never leave children, pets or anyone unattended in parked vehicles.
Residents are urged to follow local public health advice and continue monitoring Environment Canada alerts and forecasts. Severe weather reports can be emailed to ONstorm@ec.gc.ca or posted on social media using #ONStorm.
