Woodbine Entertainment Group management made the decision to cancel after consulting with the Ontario Horsemen's Benevolent and Protective Association and Ontario Racing Commission veterinarians. The temperature in Toronto is expected to reach 100 degrees the afternoon of July 21.

“In the best interest of the horses and after having discussed it with the HBPA and the veterinarians, it's the right decision to cancel Thursday's Thoroughbred card," said Steve Koch, WEG vice president of Thoroughbred racing.

Woodbine will remain open for simulcasts, and live racing is expected to resume July 22 with a post time of 2 p.m. EDT.

Colonial Downs in Virginia said it canceled racing because of extreme heat. Post time had been set for 5 p.m. The next scheduled day of racing at Colonial Downs is July 23.

Monmouth officials said they expect "excessive heat and extreme humidity" July 22 in New Jersey. Thus, the Friday program will shift to Monday, normally a dark day; the card will not be redrawn.

“Our main concern is for the safety of our horses and jockeys,” Monmouth vice president and general manager Robert Kulina said. “With temperatures expected to reach 100 degrees combined with high humidity, we had no choice but to reschedule the program to Monday.”

Live racing is scheduled to resume at Monmouth July 23 with a 12-race card.