Southern Ontario is heating up

CTV News

11-07-2025

The splash pad the the Doon Pioneer Park Community Centre in Kitchener. (July 17, 2020)
Another heat warning has been issued for southwestern Ontario.
Environment Canada said Friday marks the start of a prolonged period of higher temperatures and humidity in Waterloo Region, Guelph, Brantford, Woodstock and Toronto.
Daytime highs could range from 29 degree Celsius to 32 degrees Celsius, but with the humidex, it could feel closer to 35 or 40.
Overnight temperatures, meanwhile, are only expected to drop to 19 degrees Celsius or 23 degrees Celsius.
According to the agency, southern Ontario may not get a break from the heat until Thursday.
map
Heat warning for southern Ontario on July 11, 2025. (Source: Environment Canada)
Signs of heat illness
Heat illness is a serious concern when the mercury rises, especially in older adults, infants, young children, pregnant people, those with physical or mental illnesses, people with mobility issues, those who work outside and the homeless community.
Symptoms of heat exhaustion include:
Headache
Nausea or vomiting
Dizziness or fainting
Extreme thirst
Dark urine and decreased urination
Intense fatigue
Confusion or lack of coordination
Skin rash
Muscle cramps
Heavy sweating
Rapid breathing and heartbeat
Heat stroke, meanwhile, is considered a medical emergency.
Those symptoms include:
High body temperature
Very hot, red skin
Confusion or change in consciousness
Dizziness or fainting
No sweating
If someone is experiencing heat stroke, experts advise moving them to a cool place, giving them water and placing ice packs on their body. Call 911 immediately.
The Waterloo Region Association of Professional Paramedics is also warning that a graphic circulating online about heat stroke and heat exhaustion contains misleading information.
Beating the heat
The key to avoiding heat illness is to plan ahead.
Here are a few things to keep in mind:
Know the weather forecast before going outside
Modify your plans according to the weather
Drink plenty of cool liquids, especially water, even before you feel thirsty
Avoid drinks that are high in sugar, caffeine or alcohol
Wear loose-fitting, light-coloured clothing made of breathable fabric
Seek shade
Avoid sun exposure if you can
Take breaks as needed
Avoid using your oven
Take a cool shower or bath
Take a break by spending a few hours in a cool place
Close blinds and shades,
Turn on air conditioning or use a fan
Cooling centres
The best way to get relief from the heat and humidity is to seek out a designated cooling centre.
The Region of Waterloo has locations listed on their website. They include libraries, community centres, museums and regional offices.
The map also includes a list of public swimming pools and splash pads.
Protecting your pets
Leaving pets inside a hot vehicle, even for a few minutes, may be dangerous.
Dogs can experience heatstroke, which could lead to organ failure and, ultimately, death.
Signs of an overheated pet include:
Excessive panting
Drooling
Vomiting
Collapsing
Lethargy
Tongue can appear red or hang out of their mouth
If your pet is suffering from the heat, it's a good idea to gradually cool them down. Experts suggest using a cool blanket or towel that is wet. Avoid using ice.
Owners should keep pets at home when the temperature climbs but if they need to go outside, keep them off the pavement as much as possible, only go for a short walk, or take them out in the morning or evening when it's cooler.