The heat warning continues in the region, but a cold front is on the way.
The warning issued by Environment Canada remains in effect for Chatham-Kent, Windsor-Essex, and the London area.
This will be the most significant heat event in the past few years.
Daytime highs will be near the mid thirties with humidex values near the mid forties. Overnight low temperatures are expected to be in the low twenties, providing little or no relief from the heat.
Temperatures will cool down by Friday with the passage of a cold front.
Extreme heat affects everyone, but the risks are greater for young children, pregnant women, older adults, people with chronic illnesses, and people working or exercising outdoors.
Symptoms of heat illness include swelling, rash, cramps, fainting, heat exhaustion, heat stroke, and the worsening of some health conditions.
Never leave people or pets inside a parked vehicle.
This story will be updated and monitored as necessary.