Santé Montréal


click on the picture to enlargeWho is most vulnerable to heat?

  • Older people (aged 65 and over)
  • People with chronic diseases
  • People with mental health problems (especially schizophrenia and alcohol or drug addiction)
  • Children 0 to 4 years old are also vulnerable to heat.

What can you do to help people vulnerable to heat?

  • Check in on them regularly.
  • Make sure they’re following prevention advice and help them, if needed.
  • Take them to a cool or air-conditioned place (shopping mall, library, movie theatre, etc.) .

How can you prevent heat-related health problems? 

  • Spend a few hours a day in a cool, preferably air-conditioned place.
  • Drink a lot of water, even before you feel thirsty.
  • Reduce physical effort.

To find out more, see the information sheet It’s really hot! (PDF).

This document is available in  arabe, chinois simplifié, chinois traditionnel, créole, espagnol, frenchitalien et portugais (PDF).

Children 0 to 4 years old

To find out about precautions to take, see the documentation (PDF).

This document for parents and other caregivers of children 0 to 4 years old is available in other languages: arabe, bengali, chinois, espagnol, frenchpanjabi, tamoul, vietnamien (PDF).

What are the symptoms to watch for?

  • Exhaustion (fatigue)
  • Dehydration (dry mouth)
  • Headaches
  • Dizziness
  • Confusion
  • Fainting 

If these symptoms are present, call Info-Santé at 8-1-1 or consult a health professional. 

If there is fever in addition to those symptoms, this may be heatstroke, which is a medical emergency. In this case, call 9-1-1 to get help. 


What's the difference?

Oppressive heat 

  • The temperature reaches 30 °C with a Humidex of 40 or more.
  • Environment Canada issues a warning.
  • The main effect of heat on the population is discomfort. 

Extreme heat

  • Three consecutive days or more when the average temperature reaches 33 °C during the day and doesn’t drop below 20 °C at night


  • The temperature doesn’t drop below 25 °C for two consecutive nights.
  • Extreme heat can cause vulnerable people’s health to deteriorate rapidly and can even lead to death.