SYDNEY -- Dangerous heat is roasting parts of Australia with temperatures that haven't been seen in decades. The temperature in Sydney hit an almost 80-year high of 47.3 degrees Celsius, or 117 Fahrenheit, on Sunday -- a sharp contrast to the bitter cold that has gripped much of the U.S.

The temperature was just shy of the city's all-time high of 47.8 C (118 F), set in 1939.

New South Wales Police Deputy Commissioner Catherine Burn said the state's heat wave plan had been activated to respond to "severe to extreme heat conditions."

Spectators sit in the sun with their shirts off as Sydney experiences a heat wave during day four of the Fifth Test match in the 2017/18 Ashes Series between Australia and England at Sydney Cricket Ground on Sun., Jan 7, 2018 in Sydney, Australia. Getty

Thousands were left without power, and total fire bans were put in place as officials warned of a severe danger. Residents were urged to drink extra water and limit their time outdoors because of air pollution resulting from the hot weather.

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Players participating in the Sydney International tennis tournament were forced off the court Sunday by the event's organizers after temperatures exceeded 104 F (40 C), BBC News reports.

The heat forced France's Kristina Mladenovic to retire midway through her match against Australia's Ellen Perez. "43 degrees but probably 50 on court when started," Mladenovic tweeted. "I'm sorry to the fans, I think it's the first time in my career I retired [from] a match."