Extreme Heat

There are many fun ways to enjoy hot weather, but it's important to remember that very hot temperatures can be dangerous for your health. Some people are more at risk than others. Planning ahead and taking simple steps can help keep you and others safe.

About Heat Warnings

When the weather gets very hot and humid, Heat Warnings may be issued. Lakelands Public Health shares information about heat risks, ways to stay safe, and places in the community that can help.

Environment and Climate Change Canada (ECCC) announces heat warnings when the weather is very hot or humid and could be dangerous for people's health.

The warnings use the colours yellow, orange, and red to show how serious the heat is. These warnings:
  • Give people time to get ready and change their plans for going outside
  • Warn people who may be at risk during hot weather (and those who support them)
  • Share tips on staying safe and healthy during very hot conditions
Lakelands Public Health shares these warnings to help people stay safe when it's very hot. 

Agencies and service providers can sign up to get email alerts when heat warnings are issued. Sign up for Lakelands Public Health Extreme Temperature and Poor Outdoor Air Quality Emails

Heat warnings may happen when:

  • There are two or more days with daytime temperatures expected to reach 31°C or higher and the nighttime temperatures are 20°C or higher
         OR
  • There are two or more days when the humidex is expected to reach 40°C or higher
Most heat warnings are yellow, which means moderate impact.
ECCC might issue orange or red warnings for serious heat. They look at things like:
  • Extended heat waves
  • Unusual temperatures for the region
  • More risks, such as power outages

No heat warnings are currently in effect.

Sign Up: Extreme Weather Alerts

Receive extreme weather alerts directly to your mobile device.

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How Hot Weather Can Affect Your Health

Spending time in very hot weather can affect your health. Heat can cause dehydration (your body loses too much water) and heat exhaustion. Signs can include swelling, rashes, muscle cramps, and fainting. It can also make existing heart, lung, and other health problems worse. Heat stroke is a medical emergency and needs medical attention right away.

Extreme heat can affect anyone but some people are at more risk. Signs of heat illness can show up right away but sometimes, it can take a few days. Watch for warning signs of heat illness and take steps to stay safe. Learn more below.

Extreme heat can affect everyone, but some people are at higher risk. This is often because of a person’s ability to cool off or regulate their body temperature.

The risk of extreme heat is greatest for:

  • Older adults
  • Infants and young children
  • Pregnant people
  • People with long-term health conditions (like heart, lung, or mental health conditions)
  • People taking certain medications
  • People who spend a lot of time outdoors (work or exercise)
  • People experiencing homelessness
  • People with lower incomes
  • People who live alone or are isolated
  • People with cognitive impairment or decreased mobility
  • People who use substances, including drugs or alcohol

The more risk factors a person has, the higher their risk is of getting sick from the heat.

When the power goes out during hot weather, risks increase even more. Indoor temperatures can get very hot, very quickly when fans and air conditioners or heat pumps stop working.

Heat exhaustion is a type of heat illness that happens when your body gets too hot. It can happen when spending a short time in hot weather that your body is not used to, or after a few days of very hot weather. While dangerous, it is not as serious as heat stroke.

Signs and symptoms of heat exhaustion include: 

  • Heavy sweating 
  • Extreme thirst  
  • Skin rash 
  • Paleness or clammy skin
  • Muscle cramps 
  • Tiredness 
  • Weakness
  • Dizziness or fainting  
  • Headache 
  • Nausea or vomiting 
  • Dark urine
  • Children may have changes in behaviour, like having tantrums or feeling tired

Watch for early signs of heat exhaustion in yourself and others. It can quickly turn into a serious problem, like heat stroke. If you notice signs of heat exhaustion, stop what you are doing and take steps to cool down.

Steps to cool the body during heat exhaustion:

  • Move to a cool place 
  • Drink non-alcoholic liquids (water is best) 
  • Rest 
  • Take a cool shower, bath, or sponge bath 
  • Wear lightweight clothing 

If heat exhaustion isn't treated, it can quickly lead to heat stroke. Call 911 if symptoms continue or get worse.

Heat stroke is a medical emergency! Call 9-1-1 if you, or someone around you, is showing signs of heat stroke.

Signs and symptoms of heat stroke include:

  • Body temperature over 39°C (102°F)
  • Hot, red skin that may feel dry
  • Fainting or passing out
  • Throbbing headache
  • Feeling dizzy
  • Feeling sick to your stomach or throwing up
  • Trouble speaking clearly
  • Unusual coordination problems
  • Fast breathing or faint, fast heartbeat
  • Feeling very thirsty
  • Feeling confused or disoriented
  • Very little dark urine

While waiting for medical help, cool the person right away:

  • Move the person to a cool place if possible
  • Apply cold wet towels or icepacks to large areas of the skin 
  • Fan the person

Can you give the person a drink?

  • Most people with heat stroke feel confused or drowsy, so it may not be safe for them to drink
  • If the person is awake and alert, help them sit up. If they can swallow safely, give them cool water or a sports drink. Let them drink slowly. Stay with them and watch them closely

Reduce Your Risk in Hot Weather

Heat illnesses can be prevented. Read the sections below to learn how to protect yourself and others during hot weather, prepare your home, and access helpful resources.

1. Stay Hydrated

  • Drink water often and before you feel thirsty to replace fluids. Exposure to heat will cause your body to lose fluids through sweat.

2. Stay Cool

     A. Try to keep your home comfortable

  • Close blinds or shades and open windows if outside is cooler than inside.
  • Note: When it is hot but there is also smoke in the air, stay cool first.
  • Turn on air conditioning, use a fan, or move to a cooler are of your living space. Sleep in the coolest room possible.
  • Prepare meals that don't need to be cooked in your even (e.g., BBQ or a fresh salad).

     B. Cool your body

  • Take cool showers or baths until you feel refreshed.
  • Fans can support air flow and cooling by speeding up sweat evaporation, but they don't work well in extreme heat. They can even cause overheating. Do not rely on fans as your primary cooling method during extreme heat events. See more tips about fan use.

     C. Check the indoor temperature

  • For people at risk from heat, health issues increase when indoor temperatures are higher than 26°C (79°F).
  • Indoor temperatures above 31°C (88°F) are dangerous.
  • If your home is hot, visit a cool public space. Try a cooling centre, community centre, library, or a shaded park.

3. Limit your time outdoors and prepare yourself

  • Plan and schedule outdoor activities when it's coolest. Avoid intense physical activity in the heat.
  • Limit direct exposure to the sun and heat. Practice sun safety.
  • Wear light-weight light-coloured clothes. Choose loose-fitting styles. Don't forget a wide-brimmed hat.
  • Never leave anyone, especially children or pets, in a parked vehicle. Check the vehicle before locking to make sure no one is left behind.

4. Check on family, friends, and neigbours  

  • Learn about Heat Health Check-ins.
  • If you have air conditioning, invite family or friends over who need it.

5. Know when to get help

  • Pay attention to how you and those around you feel.
  • Watch for signs of heat-related illness.
  • If you have signs of heat illness, connect with a healthcare provider. Health 811 is available 24/7 for non-urgent health concerns (dial "811" or TTY: 711).

Climate change is causing average temperatures in our region to increase. The region will see many more very hot days (30°C or hotter) over the next several decades. This means that heat events or “heatwaves” are likely going to happen more often and be hotter or longer-lasting. Visit the Climate Change webpage for more information on climate change.

To prepare for increases in extreme heat in our community:  

Be Aware  
  • Stay up to date on weather forecasts and alerts. 
  • Get alerts with Environment Canada’s WeatherCAN app.   
Have a Plan  
  • Know where the cool spaces are in your home (e.g. basement).
  • Make sure your cooling equipment works well. This includes your air conditioning and fans.
  • If your home is very hot and you don’t have air conditioning, make a plan to stay with family or friends who do.
  • Find air-conditioned or cool spots in your area where you can go such as community centre, library, stores or shaded park. Plan for help with transportation if needed.
  • Talk to family, friends and neighbours to see how they are preparing for the heat. Create a plan to support each other and check in multiple times a day with people at higher risk.
  • Review your personal emergency plan in the case where a power outage occurs during a heat event. Find resources on our Power Outages webpage.
Consider Home Upgrades

The risk of food-borne illnesses goes up in summer. Harmful bacteria thrive in warm, damp places. Here are some outdoor food safety tips to keep you safe and healthy in hot weather:
  • Don’t keep food at room temperature for more than one hour on hot summer days.
  • Don’t leave groceries or food in the car. Bring a cooler with ice. It will help keep perishable foods fresh while you drive. The temperature inside the cooler should be at or below 4°C (40°F).
  • Marinate or thaw frozen meat in the fridge or in a cooler with ice. Don't do it on the counter at room temperature.
Always remember to keep food out of the temperature danger zone of 4°C to 60°C (40°F to 140°F). Harmful bacteria can grow in as little as two hours in this temperature range.

Visit Food Safety | Canada.ca for more information.

Heat Stroke is a medical emergency. Call 9-1-1 if you or someone nearby shows signs of heat stroke. See the section above for more information about heat stroke.

Extended exposure to heat and dehydration can contribute to other medical emergencies for people with pre-existing health issues like:
  • Cardiovascular Disease
  • Respiratory Illnesses
  • Diabetes
  • Kidney Disease
  • Mental Health Conditions
Call 911 if you or someone you know is having a medical emergency,

If a heat-related emergency is declared in the region, stay informed. Follow Lakelands Public Health and your local municipality on social media and listen to local radio stations and news channels for current information. Contact your local municipality to find out what the emergency supports are for your community.

During heat events, if you can, check in on older adults, people who live alone, and other people who are more at risk. You don't need any special training and you can use the tools linked below to help.

Check in on others a few times a day and continue to check in for a few days after the heat event ends because it can still be hot indoors.

Step-by-step instructions to do a heat health check-in:

Video backgrounders and training for how to use these tools are coming soon!

Other Resources:

Find a Community Cooling Centre Near You

For current information about cooling centres and other community supports, please visit the City of Kawartha Lakes website or contact the municipality at 705-324-9411 (toll‑free 1‑888‑822‑2225) for assistance.

For current information about cooling centres, community supports, or local services, please visit the respective municipal websites or contact their offices directly:

For current information about cooling centres, community supports, or local services, please visit the respective municipal websites or contact their offices directly:

For current information about cooling centres, community supports, and other local services, please visit the City of Peterborough’s website or by phone at: 705‑742‑7777 (toll‑free 1‑855‑738‑3755)

For current information about cooling centres, community supports, or local services, please visit the respective municipal websites or contact their offices directly:

For up‑to‑date information about cooling centres, supports, and services, please visit their official websites or contact their band offices directly:

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