Extreme Heat Warning in Effect - Beginning September 1, 2026
September 1, 2026
Environment and Climate Change Canada (ECCC) have issued a (Yellow) Heat Warning beginning Tuesday, September 1, and extending through to Wednesday, September 2, and possibly lasting into Thursday, September 3, 2026. A Yellow weather alert indicates that conditions are expected to pose an increased risk to health and daily activities, particularly for those who are more vulnerable to extreme heat. Heat is expected to build throughout the week, with daytime high temperatures ranging from 30°C to 32°C and overnight lows of 20°C to 23°C. Because temperatures are not expected to cool significantly overnight, the risk of heat-related illness will increase.
We are encouraging community members to be prepared and take precautions, be safe and check in on family, friends, and neighbours – especially those who may be more vulnerable to extreme heat.
Heat Warnings are issued when one or more of the following criteria are met:
Environment and Climate Change Canada issues a forecast calling for a daytime high of 31°C or higher and a forecast low of 20°C or higher for two consecutive days, or;
Environment and Climate Change Canada issues a forecast calling for a Humidex of 40 or higher for two consecutive days, or;
Environment and Climate Change Canada Forecasters anticipate that actual temperatures and humidex values in London and Middlesex County will reach the thresholds noted above.
The Middlesex-London Health Unit reminds the public to take steps to stay cool and to keep hydrated during this heatwave and recommends the following tips to avoid the risks of heat-related illness:
Drink plenty of water and natural juices throughout the day, even if you don’t feel very thirsty.
Never leave a child or pet in a parked car or sleeping outside in direct sunlight.
Avoid drinking caffeinated or alcoholic beverages, including coffee and cola.
When possible, avoid spending too much time outdoors. If you must be outside, seek shade as much as possible and plan outdoor activities in the early morning or evening.
Wear a wide-brimmed hat when outdoors.
Keep shades or drapes drawn and blinds closed on the sunny side of your home.
Avoid turning on electric lights in your home.
Take a cool bath or shower periodically or cool down with cool, wet towels.
Avoid intense or moderately intense physical activity.
Use fans to draw cool air at night, but do not rely on a fan as a primary cooling device during extended periods of excessive heat.
Reduce the use of personal vehicles and unnecessary idling.
Avoid using oil-based paints and glues, pesticides, and gas-powered small engines.
Additional Resources:
For an explanation of the colour-coded weather alerts, visit the Environment Canada website.
For a list of cooling resources in the City of London, including cooling centres, splash pads, park washrooms, water fountains, indoor pools and supports for individuals experiencing homelessness, visit https://london.ca/StayCool.
For a list of cooling resources in Middlesex County, including cooling centres, splash pads, and pools, visit: https://library.middlesex.ca/Locations or Swimming Pool and Splash Pads | Visit Middlesex.
For more information on heat-related illnesses visit: www.healthunit.com/community-safety/safety-outdoors/extreme-heat/.