Extreme heat

person drinking water on a sunny day after running in a public park

Extreme heat can be very dangerous. Learn the symptoms of heat stroke, heat exhaustion and how to prepare for the heat season to protect your health and that of your neighbours, friends and family.

People at higher risk

Different people respond differently to heat, and some people are at higher risk of experiencing health effects. Staying cool is especially important for the following groups of people:

  • Older adults, aged 60 years or older
  • people who live alone
  • people with pre-existing health conditions such as diabetes, heart disease or respiratory disease
  • people with mental illness such as schizophrenia, depression, or anxiety
  • people with substance use disorders, including alcohol
  • people with limited mobility
  • people who are marginally housed
  • people who work in hot environments
  • people who are pregnant
  • infants and young children

Other people can be affected by heat too. Everyone responds differently, so listen to your body. 

Health effects of heat

Extreme heat events, also known as "heat waves," can cause a number of heat-related illnesses, and can lead to an increase in deaths. Heat-related illness is an umbrella term for conditions caused by heat, such as heat rash, sunburn, heat cramps, heat exhaustion, and, the most severe, heat stroke. 

Signs of heat exhaustion include:

  • Heavy Sweating
  • Dizziness
  • Nausea or Vomiting
  • Rapid Breathing & Heartbeat
  • Headache
  • Difficulty Concentrating
  • Muscle Cramps
  • Extreme Thirst
  • New Skin Rash
  • Dark Urine & Decreased Urination 

Anyone with signs of heat exhaustion should move to a cool space, drink water, and apply cool water to large areas of the skin (cool bath, shower or wet their clothes). Take these steps right away because heat exhaustion can quickly develop into heat stroke, which is a medical emergency. 

Signs of heat stroke include:

  • High Body Temperature
  • Fainting or Drowsiness
  • Confusion
  • Lack of Coordination
  • Very Hot and Red Skin

Heat stroke is a medical emergency. Seek medical attention immediately at an emergency room or urgent care centre. Call 911 if necessary. While waiting for help, cool the person right away by moving them to a cool space if possible, and apply cool water to large areas of the skin (cool bath, shower or wet their clothes). 

Protect yourself and others from heat

Spending time in a cool space and drinking plenty of water is the best way to prevent heat-related illnesses

  • Seek cooler indoor and outdoor spaces (i.e. a local community center, library or mall)
  • Use water to cool off by taking a cool shower or putting a part of your body in a cool bath
  • Wear a wet shirt or apply damp towels to your skin to cool down
  • Drink plenty of water and other liquids to stay hydrated
  • Wear loose fitting and light-coloured breathable clothing
  • Limit activity, especially during the hottest hours of the day (generally 2 p.m. to 4 p.m. in B.C.)
  • Close windows and pull indoor/outdoor shades/blinds around 10 a.m. to trap the cooler air inside and block the sun
  • Open windows and doors around 10 p.m. to let the cooler overnight air in (check the outdoor temperature is indeed lower than indoors)
  • Use multiple fans strategically to help move cooler air into the home overnight
  • Use exhaust fans, usually located in kitchens and bathrooms, to move warmer indoor air to the outside, and open windows to pull in cooler outdoor air overnight
  • Consider getting an air conditioner for your home; if you have air conditioning be sure to turn it on
  • Monitor indoor temperatures for yourself and those you are checking on
  • Watch for symptoms of heat exhaustion and heat stroke
  • Wildfire smoke can also cause health problems. During both wildfire smoke and heat events consider also filtering your air using HEPA air cleaners. Find out more about wildfire smoke.

Check in on neighbours, friends and family

During previous heat events, a large proportion of the people who died were at home and socially isolated. Check in on your neighbours, friends and family often to ensure they are able to stay cool, and have a plan in place. This can save lives.

The National Collaborating Centre for Environmental Health (NCCEH) has developed a guide designed to help support people doing heat checks by providing all the key information and guidance in a 5-page package. This tool has been co-developed with Dr. Glen Kenny and his heat stress research group at the University of Ottawa.

NCCEH Health checks during extreme heat events guide

In spring 2022, the VCH Healthy Environments team engaged local governments and community organizations to learn what they need to help them conduct heat check-ins to support community members. Partners identified the need for information on how to run check-ins and answers to expected common questions among staff and check-in recipients. Heat check-ins happen in a variety of settings and by staff or volunteers with diverse training. Given the wide context, this framework was created so organizations may select information that is most relevant to their setting to develop their own organizational check-in plans.

VCH Heat check-in support framework for non-governmental organizations


Heat warnings and extreme heat emergencies

In response to the 2021 heat dome, multiple health sector partners and Environment and Climate Change Canada (ECCC) have developed a BC Heat Alert and Response System (BC HARS) for the summer of 2022. This two level alert system lays out the criteria that ECCC will use to issue a Heat Warning (Level 1) or an Extreme Heat Emergency alert (Level 2), the appropriate public health messaging for both types of alerts, and the recommended actions for health sector and other partners. The province will continue to refine and improve the BC HARS in the years ahead. Read more about the BC HARS on the BCCDC website.

Cooling centres and clean air spaces

During a heat warning or alert, it is important to spend time in cool spaces. When outdoor temperatures are high, even workplaces and homes can be very hot and increase the risk of heat illness. Several cities and towns in the Vancouver Coastal Health (VCH) region operate specialized cooling centres, or encourage people to use other public spaces to cool down (like libraries and community centres). Misting and water fill station stations may also be provided during a heat event.

Cooling centres and clean air spaces

In the summer of 2021, the City of Vancouver and Vancouver Coastal Health conducted a self-reported survey of indoor temperatures, with support from the BC Centre for Disease Control. This information helps us better understand the relationship between indoor and outdoor temperatures and building characteristics across the region. The goal of this work is to help inform recommendations for achieving cool temperatures inside existing buildings and help prevent heat illness.

Read the results of the Vancouver Indoor Air Temperature Survey.

Participate in this year's survey! Sign up to be notified when the survey is live at

Extreme heat resources

For the public

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For local governments

For long-term care and child care facilities

For health professionals

For landlords and stratas

For businesses

For harm reduction

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