Hot temperatures prompted heat warnings in parts of Saskatchewan, Manitoba, Ontario, Quebec and surrounding areas.
The rise came suddenly after a prolonged warm spell in Ontario, its longest since 1934, with humidex making it feel hotter still.
Manitoba also shattered a daily high mark temperature record during the same stretch.
Metro Vancouver hit nearly 31 C early in the week earlier this week before rain starts Tuesday.
Officials told residents to avoid the sun when danger peaks.