Heat warnings have stretched into their third straight day across most of eastern Ontario and western Quebec.
Many of the warnings were first issued Thursday by Environment Canada.
Daytime highs across much of the region were around 30 C on Saturday, with similar highs expected on Sunday and humidex values that approach 40.
In Ottawa, Sunday’s high is 30 C, while the humidity could make it feel more like 38.
As of 5 p.m. Saturday, there were no warnings in place for communities in the southernmost reaches of eastern Ontario like Kingston, Belleville and Napanee, as well as to the west in places like Bancroft and Barry’s Bay.
Environment Canada also issued a severe thunderstorm warning for the Maniwaki, Que., area late Saturday afternoon.
Overnight lows could stay above 20 C in some places, Environment Canada said.
July was Ottawa’s eighth straight month with an average temperature higher than the standard set in the 1980s, 90s and 2000s.
Extreme heat can pose significant health risks to everyone, but certain groups are particularly vulnerable. These include older adults, infants and young children, pregnant people and those with physical or mental health conditions.
Ottawa Public Health offers an interactive map of places to stay cool throughout the city, including pools, libraries, splash pads and community centres, plus fountains. Other health authorities and municipalities have shared similar maps.
Everyone is being asked to avoid exercising during peak heat times, staying inside where possible — especially in spaces that are being cooled — and drinking plenty of fluids.
For the nation’s capital, a cooler air mass is expected to arrive Sunday night, Environment Canada said.