Heat Waves: Before, During & After

A young boy walks through a water sprinkler

We may think of Canada as the winter capital of the world, but summers can get very hot. A prolonged period of heat can become dangerous for many people.

Prolonged exposure to extreme heat can result in heat-related emergencies, such as heat cramps, heat exhaustion, and heat stroke. The best way to protect yourself and your family in case of a heat wave is to follow these steps:

  • Stay hydrated and cool.
  • Check with your neighbours, friends and those at risk.
  • Be prepared for power outages, and have an emergency plan in place.
  • Check the contents of your emergency kit in case of a power outage.


  • Listen to local news and weather reports for heat warnings.
    • A heat warning, as defined by Environment Canada, means daytime and nighttime temperatures or humidex values are expected to be higher than the average high temperature for 2 or more days in a row.
    • Know the humidex rating – it combines the temperature and humidity to indicate how hot the weather feels to the average person.
  • Find ways to keep cool before hot weather starts.
    • Arrange air conditioning and fans to help keep your home cool.
    • Find out where you can go to get cool such as public libraries, malls, and municipal cooling centers.
    • Discuss heat safety with members of your household. Have a plan for wherever you spend time – home, work and school – and prepare for possible power outages.
  • Get trained in first aid to learn how to treat heat-related emergencies.
  • Make sure you know those who are most at risk in your neighbourhood, such as the elderly, children and those who are sick or in need of extra assistance.
  • Further information for heat wave planning can be found online at on the Sun Safety section of the Public Health Agency of Canada website.


Stay hydrated and cool
  • Drink plenty of cool fluids, even if you don’t feel thirsty, and check in with children and seniors to make sure they are drinking regularly.
    • Avoid caffeine and alcohol because they can cause dehydration, which stops your body from controlling its temperature properly
  • Avoid being outside during the hottest part of the day (typically between 10 a.m. and 2 p.m.).
  • Dress for the heat and for your activity level:
    • Wear light, loose clothing to let air circulate and heat escape.
    • Always wear a hat and apply sunscreen with SPF 15 or higher before going outside.
  • Slow down your activities as it gets hotter. Move indoors and don’t work, exercise, or play outside for an extended period of time.
    • Take frequent breaks in a cool or shady area and use a buddy system if you need to be outside when it's hot.
  • Check on your pets and animals frequently – make sure their needs for water and shade are met.

Check with your neighbours, friends and those at risk.
  • Pay close attention to how you and those around you feel. Check on vulnerable family members, friends and neighbours (such as children, the elderly and ill) who may require assistance.
    • Never leave children or pets alone in enclosed vehicles.
    • Anyone who experiences a sunburn should immediately move out of the sun, move to a cool area and consume extra fluids for the days following.
    • A severe sunburn may require medical attention if it results in display blisters, facial swelling, nausea, fever or severe chills, rapid pulse or breathing, signs of dehydration, etc.
  • Heat cramps, heat exhaustion, or heat stroke, can happen to anyone who stays in the heat and sun for too long.
    • Watch for symptoms of heat illness, such as:
      • Dizziness or fainting
      • Nausea or vomiting
      • Headache
      • Rapid breathing and heartbeat
      • Extreme thirst
      • Decreased urination with unusually dark yellow urine
      • Changes of behaviour in children
    • Heat stroke is a medical emergency. Call 911 or your local emergency number if you are caring for someone who displays:
      • Signs of heat illness
      • Unconsciousness
      • Confusion
      • Or has stopped sweating
Visit www.redcross.ca/heat for more heat safety information.


  • Open windows and blinds to allow fresh air to circulate through your home.
  • Check on neighbours, friends and family, especially those at risk.
  • Continue to stay hydrated by drinking water.

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