Environment Canada and the Middlesex-London Health Unit have issued a heat warning for Tuesday and Wednesday for London, Ont., and nearby areas.
Meteorologists with Environment Canada are calling for a high of 31 C for both days with humidex values in the upper 30s.
Slightly cooler temperatures are expected on Thursday with a high of 29 C.
Londoners can expected a mix of sun and cloud on Tuesday with a chance of showers, and cloudy skies with showers on Wednesday.
The heat warning is in effect for London, Parkhill, Strathroy, Komoka and Middlesex County.
Londoners are reminded to watch for the effects of heat illness, which include swelling, rashes, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.
Symptoms of heat illness include dizziness, nausea and vomiting, rapid breathing and heartbeat, extreme thirst and decreased urination with darker urine.