Updated7/24/2025 00:40:00
 
Forecast - Environment Canada
Heat Warning
7:07 p.m. EDT Wednesday 23 July 2025

Heat Warning in effect for:
  • City of Toronto
A heat event is expected to begin Thursday.

Thursday:
Daytime high temperatures up to 35 degrees Celsius.
Peak humidex values up to 44.
Nighttime low temperatures of 20 to 23 degrees Celsius, providing little relief from the heat.

Friday:
Daytime high temperatures near 30 degrees Celsius.
Peak humidex values near 40.
Nighttime low temperatures near 21 degrees Celsius, providing little relief from the heat.

When:
Thursday and Friday. Possibly continuing through the weekend for some areas.

Additional information:
The hottest conditions are expected on Thursday. While daytime high temperatures will not be as extreme on Friday and into the weekend, nighttime lows are expected to remain warm throughout.

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.

For more information: https://www.canada.ca/en/health-canada/services/climate-change-health/extreme-heat/how-protect-yourself.html https://www.canada.ca/en/health-canada/services/climate-change-health/extreme-heat/who-is-at-risk.html

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ONstorm@ec.gc.ca or post reports on X using #ONStorm.

 Extended Forecast - Environment Canada
  Thu, 24 Jul
Mainly sunny
Mainly sunny
Max: 34°C
Fri, 25 Jul
Chance of showers (40%)
Chance of showers
Max: 30°C
Sat, 26 Jul
A mix of sun and cloud
A mix of sun and cloud
Max: 27°C
Sun, 27 Jul
A mix of sun and cloud
A mix of sun and cloud
Max: 25°C
Mon, 28 Jul
A mix of sun and cloud
A mix of sun and cloud
Max: 31°C
Tue, 29 Jul
Cloudy
Cloudy
Max: 29°C
Tonight
Clearing
Clearing
Min: 20°C
Night
Chance of showers (60%)
Chance of showers
Min: 23°C
Night
Cloudy
Cloudy
Min: 18°C
Night
Clear
Clear
Min: 18°C
Night
Cloudy periods
Cloudy periods
Min: 19°C
Night
Cloudy periods
Cloudy periods
Min: 21°C

Forecast

Toronto Island, ON (Issued: 3:30 PM EDT Wednesday 23 July 2025)

Tonight
Clearing early this evening. Low 20.
Thu, 24 Jul
Mainly sunny. Wind becoming south 20 km/h gusting to 40 in the morning. High 34. Humidex 42. UV index 9 or very high.
Night
Increasing cloudiness. 60 percent chance of showers late in the evening and overnight with risk of a thunderstorm. Wind west 20 km/h gusting to 40 becoming light after midnight. Low 23.
Fri, 25 Jul
Cloudy with 40 percent chance of showers. High 30.
Night
Cloudy. Low 18.
Sat, 26 Jul
Clearing. High 27.
Night
Clear. Low 18.
Sun, 27 Jul
A mix of sun and cloud. High 25.
Night
Cloudy periods. Low 19.
Mon, 28 Jul
A mix of sun and cloud. High 31.
Night
Cloudy periods. Low 21.
Tue, 29 Jul
Cloudy. High 29.

24 Hour Forecast - Toronto Island, ON

Date/Time Temp.
(°C)

Weather Conditions

LOP †
Wind
(km/h)
24 July 2025
1 AM 22 Clear (0%)  Clear 0 VR 5
2 AM 21 Clear (0%)  Clear 0 VR 5
3 AM 21 Clear (0%)  Clear 0 VR 5
4 AM 20 Clear (0%)  Clear 0 VR 5
5 AM 20 Clear (0%)  Clear 0 VR 5
6 AM 21 Mainly sunny (10%)  Mainly sunny 10 VR 5
7 AM 22 Mainly sunny (10%)  Mainly sunny 10 VR 5
8 AM 23 Mainly sunny (10%)  Mainly sunny 10 S 20
9 AM 25 Mainly sunny (10%)  Mainly sunny 10 S 20
10 AM 26 Mainly sunny (10%)  Mainly sunny 10 S 20
11 AM 28 Mainly sunny (10%)  Mainly sunny 10 S 20 gust 40
12 PM 29 Mainly sunny (10%)  Mainly sunny 10 S 20 gust 40
1 PM 31 Mainly sunny (10%)  Mainly sunny 10 S 20 gust 40
2 PM 32 A mix of sun and cloud (10%)  A mix of sun and cloud 10 S 20 gust 40
3 PM 33 A mix of sun and cloud (10%)  A mix of sun and cloud 10 S 20 gust 40
4 PM 33 A mix of sun and cloud (10%)  A mix of sun and cloud 10 S 20 gust 40
5 PM 34 Mainly sunny (10%)  Mainly sunny 10 SW 20 gust 40
6 PM 33 Mainly sunny (10%)  Mainly sunny 10 SW 20 gust 40
7 PM 32 Mainly sunny (10%)  Mainly sunny 10 SW 20 gust 40
8 PM 31 A mix of sun and cloud (10%)  A mix of sun and cloud 10 W 20 gust 40
9 PM 30 Partly cloudy (10%)  Partly cloudy 10 W 20 gust 40
10 PM 29 Chance of showers. Risk of thunderstorms (60%)  Chance of showers. Risk of thunderstorms 60 W 20 gust 40
11 PM 28 Chance of showers. Risk of thunderstorms (60%)  Chance of showers. Risk of thunderstorms 60 SW 20
25 July 2025
12 AM 27 Chance of showers. Risk of thunderstorms (60%)  Chance of showers. Risk of thunderstorms 60 SW 20
 
† Likelihood of Precipitation (LOP) as described in the public forecast as a chance of measurable precipitation for a period of time.
  Nil: 0%
  Low: 40% or below
  Medium: 60% or 70%
  High: Above 70%

Environment Canada