It's a holiday Monday across much of Canada, but some people may have to spend the day inside.
Less than two weeks after numerous daytime heat records were set across Ontario and Quebec and parts of the Prairies sweltered through a heat wave, people in Ontario and Manitoba are once again dealing with dangerous heat.
Environment Canada issued a humidex advisory for southwestern Ontario, including Windsor, Sarnia and the Niagara peninsula. Temperatures climbed into the 30s, with the humidex making it feel like 40.
The City of Toronto issued a heat alert, advising people to keep their air conditioners running, seek out opportunities to cool off and check on loved ones with known health issues.
This is the sixth time this summer Toronto has issued a heat alert in the interest of public health. The city has also issued five extreme heat alerts.
The heat could pose problems for people heading home from the cottage later on Monday. The OPP is reminding drivers to stay hydrated, as cars heat up quickly and stay hot even with the A/C running.
A humidex advisory is also in place for much of southeastern Saskatchewan, including Winnipeg and Brandon.
The advisory stretches all the way north to Dauphin, where the humidex was expected to make it feel like 43.
A cold front is expected to sweep through later on Monday, but the intense heat that has settled over the province means there's a potential for severe thunderstorms to develop.
The biggest risk for severe weather is in south-central Manitoba, from Winnipeg to just south of Thompson.