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Hot weather and heat warnings

The Region of Peel's Medical Officer of Health issues heat warnings and extended heat warnings upon notification from Environment Canada that heat thresholds have been met.

People suffer heat-related illnesses when their body temperature quickly rises and they are unable to cool themselves. The risk of heat-related illness increases with the amount of time spent in the heat, the temperature and an individual's sensitivity to heat. Although an increase in the number of hot days is dangerous, it is the combination of heat during the daytime and nighttime that causes significant increases in heat-related morbidity and mortality. This is because there is no break from the heat which is important for allowing the body to cool off.

Extreme heat can cause heat illnesses. Look out for the following symptoms of heat exhaustion:

  • Heavy sweating
  • Dizziness or fainting
  • Headache
  • Cold, pale, and clammy skin
  • Vomiting

If experiencing any of these symptoms, immediately move to a cool place, drink water, and seek help.

Heat strokes are a medical emergency. Watch for a high body temperature, confusion, dizziness or fainting, and no sweating, but very hot, red skin. Call 911 immediately and cool the person right away by:

  • Moving them to a cool place if you can.
  • Applying cold water to large areas of the skin.
  • Fanning the person as much as possible.

For more information, see Symptoms and Prevention.

During Hot Weather Conditions

Stay cool in air-conditioned spaces and drink lots of fluids, especially water. Groups at higher risk of heat-related illness include infants, young children, seniors, people with chronic and pre-existing illnesses, people on certain medications and those who are homeless or low-income earners.

Please remember to call or visit family, friends and neighbours, especially seniors who live on their own, to make sure they are alright.

Learn how to protect your health during hot weather conditions:

Environment Canada Heat Thresholds

Heat Warning: Duration – 2 days

  • Forecast daytime temperatures are expected to be at least 31°C and overnight temperatures are 20°C or above
  • Humidex is at least 40

Extreme Heat WarningExtended Heat Warning: Duration – 3+ days

  • Forecast daytime temperatures are expected to be at least 31°C and overnight temperatures are 20°C or above
  • Humidex is at least 40
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