"We're inviting the population to be vigilant for the next two days - for themselves as well as those close to them".
Besides the heat and humidity, Environment Canada is also calling for "very high" UV levels which means a higher risk of sunburn.
Dr. Stang says he doesn't fear having more frequent warnings will make people pay less attention to them.
An extended heat warning issued by the city's medical officer of health on Sunday remains in effect.
The weather agency has advised Islanders to drink plenty of water, even before feeling thirsty, and to stay in a cool place. His internal body temperature reached 108 degrees at the hospital.
"It could save a life", Genereux said.
Twelve of the dead were reported in the eastern province´s capital Montreal, said regional public health director Mylene Drouin.
At least eight people in the USA and Canada have died in the past week due to the intense heat wave affecting parts of North America.
"At the moment, it fits exactly with the features we've described: people with chronic diseases, mental health issues, people who live alone, people without air conditioning who live in apartments of more than four or six stories and obviously, in areas where there is lots of heat", she said.
In the Eastern Townships region southeast of Montreal, four deaths are under investigation to determine if they are related to the extreme heat.
He is asking residents to call a provincial health-consultation line in the event of minor health problems or to check in with friends or family and leave 911 lines free for real emergencies.
The hot temperatures and high humidity are expected to persist through at least Thursday, Environment Canada said.