Hot temperatures sparked heat warnings throughout parts of Saskatchewan, Manitoba, Ontario, Quebec and surrounding areas.
The rise came fast after a extended heatwave in Ontario, its longest since 1934, with the humidex making it feel hotter still.
Manitoba in addition broke a daily high mark record during the same stretch.
Metro Vancouver hit nearly 31 C early in the week in the early week before showers begin Tuesday.
Authorities advised residents to stay out of the sun when risk peaks.