Here you will find information on the different types of heat warnings and how to prepare for them.
Heat events, also known as heatwaves, are a series of days that have hotter than normal daytime and overnight temperatures for the region. As the climate changes, heat events will become more frequent, longer, and hotter in BC.
Heat events can affect anyone's health, but extreme heat can pose a very high risk of severe illness for some people if they do not have access to a cool indoor environment. Heat can build up indoors when the outdoor temperatures are high, and the situation can become dangerous. The longer the heat lasts, the more dangerous indoor temperatures can become, especially if they stay over 31C for long periods.
If you are at risk and it gets very hot in your home during extreme heat events, plan to go somewhere cooler, if possible.
Check for heat alerts
British Columbia has revised the heat alerting system in alignment with Environment and Climate Change Canada’s new colour-coded weather alerts. There are three new warning levels: Yellow, Orange and Red.
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Yellow Warning – Heat: This is the most common warning. This means daytime and overnight temperatures will be unusually high for at least two consecutive days. Take steps to stay cool.
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Orange Warning – Heat: This is an uncommon warning. This means daytime and overnight temperatures will be very high for at least three consecutive days. Take steps to stay cool and protect yourself and others. Check in regularly with family, friends, and neighbours who are at higher risk of heat-related illness, especially if they live alone without access to air conditioning.
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Red Warning – Heat: This is a rare warning. This means that temperatures will be dangerous, especially in indoor environments without air conditioning, much like what happened during the 2021 Heat Dome. Daytime and overnight temperatures will be much higher than usual and will get hotter every day for at least three consecutive days. Activate your extreme heat emergency plan.
With this update, the BC Heat Alert Response System has mapped the province into four zones with specific ranges of daytime and overnight temperatures that would trigger warnings for each zone.
For more information about the HARS zone and historic daytime and overnight temperatures where you live visit:
BCCDC HARS Lookup Tool
Everyone is at risk of heat-related illness, but hot temperatures can be especially dangerous for certain individuals. Older adults, especially those living alone, are at elevated risk across most of these categories:
- People with severe mental illness or cognitive impairment (e.g., schizophrenia, dementia) that may affect their ability to respond to heat
- People with multiple chronic conditions or disabilities that limit their physical ability to respond to heat
- People with chronic conditions such as respiratory disease, heart disease, neurological disease, or diabetes
- People with substance use disorders
- People who are living in poverty, marginally housed, or experiencing homelessness
- Pregnant people
- Infants and young children
Heat can also pose a health risk to people who work or exercise in hot environments:
- work on farms
- work in construction
- work in kitchens or hot industrial environments
- exercise outdoors
Preparing your space
It’s important to take precautions before a heat event occurs. You can prepare your space by:
- Identifying a cooler space in your home and setting it up so you can stay there at night, if possible. You may need to change daily living arrangements
- Finding an air-conditioned spot close by where you can cool off on very hot days. Consider staying with friends or family or finding places in your community to spend time such as movie theatres, libraries, community centres, or shopping malls
- Checking that you have a working fan. If you have an air conditioner, make sure it’s working
- Installing awnings, shutters, blinds, or curtains over your windows to keep the sun out during the day
- Getting a digital room thermometer to keep with you so you know when your home is getting too hot
Your friends and family
Checking on your friends and family and creating a plan for supporting each other during heat events can help keep everyone safer.
- Think of people you know who may be more susceptible to heat and develop a buddy system.
- Make a plan to check in with your hot weather buddy often, especially in the evening when indoor temperatures are highest. It is also good to plan a check-in for early morning, to see how your buddy has managed through the night.
- If your home is cooler, invite those who are at highest risk to stay with you during heat events, if possible.
Planning for heat resources
Your health
It’s important to know the signs and symptoms of heat-related illness so you can identify problems early on.
Signs of overheating include:
- feeling unwell
- headache
- dizziness
Overheating can quickly lead to heat exhaustion and heat stroke.
Signs of heat exhaustion include:
- heavy sweating
- severe headache
- muscle cramps
- extreme thirst
- dark urine
If you are experiencing these symptoms, seek a cooler environment, drink plenty of water, rest, and use water to cool your body.
If heat exhaustion persists, it can become heat stroke, a serious medical emergency.
Signs of heat stroke include:
- confusion
- fainting or decreased consciousness
- nausea and vomiting
- rapid breathing
- faint rapid heart rate or very high body temperature (39+)
If you or someone else experiences these symptoms, call 9-1-1. Take steps to start cooling the person down right away. Move them to a cooler area or cool shower or bath if it is safe to do so or remove clothes and apply ice packs wrapped in a towel and wet cloths, especially around the neck, armpits.
If you take regular medications, drugs, or have a health condition, ask your doctor or pharmacist whether it increases your health risk in the heat and follow their recommendations.
If you spend time outdoors, protect yourself from the sun by staying in the shade, avoiding direct sun mid-day, wearing a hat and protective clothing, using sunscreen, and wearing UV-protective eyewear. Seek cooler, breezier areas, such as large parks with water features and lots of trees.
Important: If you are experiencing extreme heat during an air quality advisory, prioritize cooling down. Heat exposure is a bigger risk than short-term exposure to poor air quality for most people.
How to cool your body
If you cannot access air conditioning and/or a cool room, consider:
- wearing a damp shawl or shirt
- sitting in a cool or tepid bath to draw heat from the body into the water
- taking a cool shower
- using a damp sheet at night
- putting an ice tray in front of a fan
- using a personal mister or spray bottle
Important: While fans can help you feel more comfortable, they are not very effective for lowering core body temperature, and they can become unsafe at temperature over 35 degrees Celsius.
Protecting your health and your loved ones
The following tips can help you manage your health during a heat event.
- Drink lots of water, even if you do not feel thirsty, especially during warm nights. Pay attention to the amount and colour of your urine. Dark yellow urine is a sign of dangerous dehydration.
- Lower your activity level and avoid intense activity. It takes time for your body to adapt to heat. If you need to do errands, do them when it is cooler outside, early or late in the day.
- Watch out for severe headache, confusion, unsteadiness, nausea/vomiting -- these are signs of heat stroke.
- If you are experiencing heat stroke, take immediate action to cool down and call for help, if needed. Heat stroke is a medical emergency.
Special considerations for children
- Children are not always able to recognize how heat events are affecting them. Ensure they stay hydrated with plenty of water.
- Apply sunscreen throughout the day; wear hats, sunglasses, and light-weight clothing in breathable materials.
- Avoid being outside during the hottest part of the day (mid-to-late afternoon).
- Seek shade, air-conditioned spaces such as community centres or libraries, splash pads, waterparks or pools.
Special considerations for pregnant people
Pregnant people can be more susceptible to heat exhaustion or heat stroke, particularly if they have chronic health conditions (such as obesity, kidney disease, or heart disease). Their heart has to work harder to cool themselves and their baby down.
- Lower blood pressure is common, particularly in early pregnancy. Warm conditions bring blood to the skin to get rid of excess heat which can potentially make blood pressure even lower. This can cause headaches, feeling light-headed or even fainting.
- Many experience Braxton Hicks contractions in pregnancy and dehydration can make these worse. Hot weather may also cause preterm birth. Anyone who experiences more Braxton Hicks-type uterine activity than usual should be checked by their health care provider.
- Drink plenty of water, find ways to stay cool, and avoid increased physical activity during hot weather.
Dangerous indoor temperatures can occur in homes and other buildings without air conditioning, especially in mobile homes and the top floors of houses and apartment buildings.
Get a digital room thermometer to keep with you so you know when your home is getting too hot.
- Sustained exposure to temperatures of 26°C or less are generally safe for everyone.
- Sustained exposure to temperatures from 26°C to 31°C may be higher-risk for the most heat-susceptible people.
- Sustained exposure to temperatures over 31°C may pose a risk for heat-susceptible populations and should be avoided whenever possible
In the evening, open windows and doors when the outdoor temperature goes down below the indoor temperature to allow cooler air to circulate through your home and cool indoor temperatures. Place fans near windows to pull cool air in and push warm air out.
Plan to sleep in the coolest space, even if that is not your bedroom. Sleeping in a basement or outdoor space will provide relief to the body overnight, if possible. Set that space up for comfort, being sure you have water to drink.
In the morning, shut windows and close shutters, curtains, or blinds to keep cooler air in and to keep the sun out. Leaving windows open during the day lets the hot air inside warming indoor temperatures.
Consider making meals that don't need to be cooked in an oven which will increase indoor temperatures.
If you do not have air conditioning, find somewhere with air conditioning especially if you are at increased risk. You can also spend time in cooler indoor spaces in the community like shopping centres or libraries.
Check on people at higher risk in-person to evaluate their health and the temperature indoors. If you cannot check in-person, ask them to tell you what it says on their thermostat or indoor thermometer. Encourage those who may not know they are at higher risk to take cool baths, sleep in the coolest room, or stay with friends.
If you have air conditioning and higher risk members of your family do not, bring them to your house, where possible.
Never leave children, dependent adults, or pets alone in a parked car. Leaving the windows open
will not help keep them cool while the car is off.
