And if the heat wasn't enough, the forecast also calls for a 60 per cent chance of rain this afternoon while humidity levels stay high.
The sweltering heat reached a high of 33.6 C at 4 p.m. on the final day of June, with a humidex reading of 43.
"Extended periods of heat and humidity like we've seen over the weekend and are expecting over the next few days can be especially challenging for seniors, young children and those with medical conditions that put them at greater risk", said Randy Walker, public health inspector with MLHU.
Dr. Mylene Drouin told a news conference today the deaths have been investigated and are linked directly to the heat wave.
Montreal city hall unveiled an "extreme heat" plan on Tuesday that includes distributing water to groups working with the homeless.
In response to the extended heat warning, the city has opened a number of cooling centres around Toronto.
Sudbury has been under a heat warning since Friday.
"What's more unique about this is the duration", said Kelly Hobelman, a meteorologist with Environment Canada.
In Toronto and Ottawa, temperatures have remained well above 30 C since Friday.
A heat warning issued by the weather agency also says humidex values of 35 C degrees or more are expected throughout the entire province.
"The most recent one was back in 2011", says Cheng.
The Salvation Army was out at Gore Park handing out bottles of water reminding people to heed the warnings and protect themselves, and police have already received a number of calls including one on Appleby Line and Upper Middle Road in Burlington where they rescued a dog from a hot vehicle where the temperature was 66 degrees.