A brief but intense heat spike will grip Sarnia early this week before a cold front brings cooler temperatures and a chance of showers, according to Environment Canada. A heat warning is in effect for the region starting Monday, July 13, with the hottest conditions expected on Tuesday.
Highs are forecast to climb from 33°C on Monday to a sweltering 37°C on Tuesday. Humidex values will make it feel like 45°C at the peak of the heat. The UV index is expected to reach 10, or very high, so sun protection is essential. Environment Canada warns that hot and humid air can worsen air quality, and the Air Quality Health Index may approach the high-risk category.
Lambton Public Health has issued an extended heat warning, urging residents to watch out for those most at risk. “LPH is reminding residents to keep an eye on the most vulnerable, such as older adults, young children, individuals with chronic illnesses, those who are pregnant, and those who work outdoors,” the agency said. People should drink plenty of water, seek shade, and never leave children or pets in parked vehicles.
Relief is in sight by midweek. A cold front arrives Wednesday, July 15, dropping highs to around 32°C. The weather pattern turns unsettled, with a 30 percent chance of showers Wednesday through Saturday. The highest chance of rain, around 40 percent, comes Friday night. Overnight lows will generally range from 17°C to 23°C through the period.
This is the second major heat event for Sarnia-Lambton in under two weeks. A heat wave from June 28 to July 4 pushed temperatures to 35.1°C but did not break any records. Environment Canada meteorologist Geoff Coulson noted that the hottest part of summer typically arrives in late July and early August, so more heat waves remain possible.
