During these hot periods, Peel Region’s Medical Officer of Health issues heat warnings and extended heat warnings upon notification from Environment & Climate Change Canada that heat thresholds have been met.
As defined by Ontario’s Ministry of Health, heat warnings are issued when there are two or more consecutive days of:
- Daytime maximum temperatures are expected to reach 31°C or warmer and overnight temperatures are 20°C or warmer.
- Humidex values that are expected to reach 40°C or higher.
Extended heat warnings are issued when heat warnings last for three or more days.
Based on Environment and Climate Change Canada’s data, Peel Region’s Medical Officer of Health is forecasting the first heat warning of the season for Mississauga, with conditions starting Sunday June 22, 2025. The warning will be in effect until further notice.
When extremely hot temperatures are forecasted, the City offers residents places to stay cool in Mississauga. These include visiting one of our swimming pools, air-conditioned libraries and community centres, and spray pads.
The following is also completed during heat warnings:
- The stay cool page is updated on the Recreation microsite.
- Social media is issued on City channels (and additional messaging follows throughout the duration of the heat warning, as needed).
- Residents can visit the City’s Extreme Heat page to learn more.
Business areas with outdoor workers adjust their operations accordingly to ensure they are meeting health and safety requirements.
We will not be issuing additional updates in advance of each heat warning. A hot weather media story has been posted on the City’s website which residents can be directed to throughout the heat season. All of the above identified actions will remain applicable for further heat warning events.