Monday could be the hottest day of the summer in Ottawa

CTV News

11-08-2025

As Ottawa sweats under a heat warning, Monday could be the hottest day of the summer so far, with a high of 35 C in the forecast.
The hot, humid weather is anticipated to continue through Tuesday or possibly Wednesday for some areas, according to Environment and Climate Change Canada.
'A cooler air mass is expected to arrive Tuesday night, bringing an end to this heat event. There is the possibility that eastern Ontario and the Greater Toronto and Hamilton Area could see hot and humid conditions continue into Wednesday,' the weather agency says.
The forecast for Monday calls for a high of 35 C with a humidex of 43 under a sunny sky.
Monday night is clear with a low of 21 C, bringing little relief overnight.
Sweltering conditions remain in the forecast on Tuesday, with another high of 35 C and a humidex of 41. There is a slight chance of showers in the late afternoon.
Officially, Ottawa has seen 0 millimetres of rain in all of August so far. A brief downpour drenched downtown Ottawa last Thursday, but many parts of the city, inlcuding the Ottawa airport, where rainfall measurements are taken, didn't see a single drop.
Wednesday's forecast is cloudy with a high of 30 C and a 30 per cent chance of showers.
Thursday's outlook is sunny.
Watch for the early signs of heat exhaustion
Signs of heat exhaustion may include:
Headache
Nausea
Dizziness
Thirst
Dark urine
Intense fatigue
Stop your activity and drink water if you start to develop these symptoms.
'Call 9-1-1 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,' Environment and Climate Change Canada says. '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.'