Today – July 15, 2025
Sunny. Hazy. High 31. Humidex 35. UV index 10 or very high.
Heat warning
A prolonged period of extreme heat and humidity continues.
What:
Daytime highs of 31 to 35 degrees Celsius and a humidex of 37 to 42.
Overnight lows of 19 to 23 degrees Celsius, providing little relief from the heat.
When:
Continuing through to Thursday night.
Additional information:
Southern Ontario will experience hot and humid conditions now through much of this week. A shift in the weather pattern late this week will likely end this multi-day period of heat and humidity Thursday night.
Take action to protect yourself and others – extreme heat can affect everyone’s health. Determine if you or others around you are at greater risk of heat illness. Check on older adults, those living alone and other at-risk people in-person or on the phone multiple times a day.
Watch for the early signs of heat exhaustion in yourself and others. Signs may include headache, nausea, dizziness, thirst, dark urine and intense fatigue. Stop your activity and drink water.
Heat stroke is a medical emergency! Call 9-1-1 or your emergency health provider if you, or someone around you, is showing signs of heat stroke which can include red and hot skin, dizziness, nausea, confusion and change in consciousness. While you wait for medical attention, try to cool the person by moving them to a cool place, removing extra clothing, applying cold water or ice packs around the body.
Drink water often and before you feel thirsty to replace fluids.
Close blinds, or shades and open windows if outside is cooler than inside.
Turn on air conditioning, use a fan, or move to a cooler area of your living space. If your living space is hot, move to a cool public space such as a cooling centre, community centre, library or shaded park.
Follow the advice of your region’s public health authority.
Plan and schedule outdoor activities during the coolest parts of the day.
Limit direct exposure to the sun and heat. Wear lightweight, light-coloured, loose-fitting clothing and a wide-brimmed hat.
Never leave people, especially children, or pets inside a parked vehicle. Check the vehicle before locking to make sure no one is left behind.
When there is an extreme heat event occurring with wildfire smoke, prioritize keeping cool.
For more information: How to protect yourself from the health effects of extreme heat
Tonight
Clear. Hazy. Low 20.
Wed, 16 Jul- Mainly cloudy with 40 percent chance of showers and risk of a thunderstorm. Wind west 20 km/h becoming south 20 late in the morning. High 30. Humidex 38. UV index 9 or very high. Night – Cloudy with 40 percent chance of showers. Low 23.
Thu, 17 Jul – Cloudy with 60 percent chance of showers. High 30. Night – Cloudy periods with 40 percent chance of showers. Low 20.
Fri, 18 Jul – A mix of sun and cloud with 30 percent chance of showers. High 26. Night – Cloudy periods. Low 17.
Sat, 19 Jul – Cloudy. High 26. Night – Cloudy with 40 percent chance of showers. Low 19.
Sun, 20 Jul – Cloudy with 60 percent chance of showers. High 28. Night – Cloudy periods with 30 percent chance of showers. Low 18.
Mon, 21 Jul – A mix of sun and cloud. High 30.
