Hot temperatures prompted heat warnings in parts of Saskatchewan, Manitoba, Ontario, Quebec and nearby regions.
The jump came fast after a long hot stretch in Ontario, its longest since 1934, with the humidex making it feel hotter still.
Manitoba in addition shattered a daily high mark record during the same stretch.
Metro Vancouver hit nearly 31 C early in the week in the early week before rain arrives Tuesday.
Public health officials advised residents to avoid the sun when danger is highest.