Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Canada Perspective Weather Desk. Data from Environment and Climate Change Canada and other national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
The live forecast above for Hot Springs points to the kind of hot weather that has settled over much of the country this week, with daytime highs climbing well above the seasonal average and little relief overnight. For residents from the interior valleys of British Columbia to the southern Prairies and parts of Ontario, this prolonged warmth brings both the pleasure of summer and the need to understand the risks of extreme heat.
What causes a heat wave?
A heat wave occurs when a strong ridge of high pressure parks over a region, trapping warm air and preventing cooling clouds or rain from forming. This “heat dome” can linger for days, compressing and heating the air beneath it. In Canada, these patterns often develop when the jet stream shifts north, allowing hot, dry air from the American southwest to surge into the Prairies or Ontario. Climate change is making such events more frequent and intense.
How does hot weather affect your body?
When the body can’t cool itself fast enough, heat stress sets in. The three most common harmful effects of heat are dehydration, heat exhaustion, and heatstroke. Dehydration reduces blood volume, forcing the heart to work harder. Heat exhaustion brings heavy sweating, weakness, and nausea—if left unchecked it can progress to heatstroke, a life-threatening emergency where body temperature exceeds 40°C. The effects of hot weather on the body also include swelling in the hands and feet, heat rash, and worsened chronic conditions such as heart disease.
Frequently asked questions
What temperature is considered hot weather in Canada?
There is no single definition, but Environment Canada typically labels a day as “hot” when the high reaches 30°C or the humidex tops 35. For hot weather Toronto and other southern cities, that threshold is met several times each summer.
What are the dangers of hot weather for seniors and children?
Older adults, infants and people with chronic illnesses are most vulnerable because their bodies regulate heat less efficiently. Heat can worsen heart and lung conditions, and children’s smaller bodies dehydrate faster. Staying in air-conditioned spaces and drinking water are key.
How does hot weather today compare to past decades?
Recent research shows the frequency of extreme heat events has doubled in many parts of Canada since the 1950s. The effects of heat waves on humans are now more pronounced, with longer stretches of hot weather temperature records being broken regularly across the country.