Hot temperatures sparked heat warnings across parts of Saskatchewan, Manitoba, Ontario, Quebec and adjacent provinces.
The rise came suddenly after a extended heatwave in Ontario, its longest since 1934, with humidex making it feel hotter still.
Manitoba additionally set a daily high mark benchmark during the same stretch.
Metro Vancouver hit nearly 31 C early in the week earlier this week before showers begin Tuesday.
Officials advised residents to avoid the sun when danger peaks.