Monday was a recording-break day for heat.
The high for June 12 was 33.1 C.
Environment Canada says that surpasses the previous record of 32.4 C set on that date 10 years ago.
A heat warning remains in effect for Toronto and most of southern Ontario but temperatures are expected to cool down by Wednesday.
Toronto's chief medical officer of health issued a heat warning Sunday, prompting the opening of cooling centres throughout the city.
Dr. Eileen de Villa is urging residents to check up on vulnerable neighbours as well.
Seven air-conditioned cooling centres have been opened in public buildings across the city:
• Metro Hall, 55 John St. (24 hours)
• East York Civic Centre, 850 Coxwell Ave. (11 a.m. to 7 p.m.)
• North York Civic Centre, 5100 Yonge St. (11 a.m. to 7 p.m.)
• Driftwood Community Centre, 4401 Jane St. (11 a.m. to 7 p.m.)
• Etobicoke Civic Centre, 399 The West Mall (11 a.m. to 7 p.m.)
• McGregor Community Centre, 2231 Lawrence Ave. E. (11 a.m. to 7 p.m.)
• Centennial Community Centre, 1967 Ellesmere Rd. (11 a.m. to 7 p.m.)
Anyone who needs more information about assistance available during a heat warning is urged to call 311.
With files from CP24 and Corinne Van Dusen