In June 2017 dozens of flights were cancelled in Phoenix, Arizona because of temperatures exceeding 120 degrees Fahrenheit/48.9 degrees Celsius.1,2
Hot air at a given air pressure is less dense, generating less lift at a given speed. At least some commercial jets were not rated to fly in air that thin.
While the temperatures that summer were fairly extreme Phoenix is surely not the hottest place one earth, or at least not alone in this range. For example Kuwait City or the Iranian city of Ahvaz3 come to mind.
How do other hot places handle extreme heat? Do they also suspend operation or do they impose specific requirements like lower maximum loads, or do they have special adaptations for the thinner air like long runways, allowing higher speeds at take-off and landing?
3 I found Ahvaz googling for hot places; I admit that I have never heard of it before even though it has more than a million inhabitants and an international airport, AWZ.