The latest in a series of heat warnings this summer has been issued.
Environment Canada says a heat episode is expected Thursday and Friday. Day time temperatures are forecast to reach the low 30 C range with afternoon humidex values in the mid to upper 30 C range.
It's expected to remain very mild overnight with lows near 20 C.
When temperatures and humidity are high, the body may not be able to cool properly, leading to heat exhaustion or heat stroke.
The heat warning is expected to end later Friday with the passage of a cold front that could trigger some thunderstorms.
Click here for Lambton Public Health's list of cooling centres.
