Ottawa public health has issued a heat advisory for the next two days.
Health authorities issue an advisory whenever a humidex of 36 or more is forecast for two consecutive days. The humidex is expected to be above 36 Friday and Saturday.
Doctors warn extreme heat and humidity can cause dehydration, heat exhaustion, heat stroke and even death.
People are being advised to drink fluids, avoid strenuous outdoor physical activity and avoid direct exposure to the sun.
They should also spend at least two hours a day in an air-conditioned location.
Infants, young children and homeless people are at greater risk from extreme heat, as are people taking medications such as anti-Parkinsons medication or antidepressants.
The temperatures are expected to hit highs of 32 and 25 degrees Celcius Friday and Saturday respectively. There is a 60 per cent chance of showers and a risk of a thunderstorm on Saturday.