Environment Canada says the extreme heat could persist through next week.
The agency updated its heat warning for the Windsor region late Saturday afternoon to indicate the hot weather will create the most significant heat event in the past few years.
Daytime highs are forecast to reach the low to mid thirties with humidex values into the mid forties.
Windsor hit the mid-40s with the humidex value Saturday.
Overnight low temperatures are expected to be in the low to mid-20s, providing little or no relief from the heat.
There was also a special weather statement in effect for Windsor-Essex and Chatham-Kent Saturday.
Environment Canada says high levels of air pollution are possible.
Hot and sunny conditions are expected to cause increasing ground-level ozone concentrations in the area.
The Air Quality Health Index has the potential to reach high risk for short periods of time in the late afternoon and early evening with deteriorating values again on Sunday.
