The weather forecast for the US city suggests temperatures could reach 120F (49C) on Tuesday.
That is higher than the operating temperature of some planes.
American Airlines announced it was cancelling dozens of flights scheduled to take off from Sky Harbor airport during the hottest part of the day.
The local Fox News affiliate in Phoenix said the cancellations mostly affected regional flights on the smaller Bombardier CRJ airliners, which have a maximum operating temperature of about 118F (48C).
The all-time record for temperatures in Phoenix is just slightly higher, at 122F, which hit on 26 June 1990.
Phoenix flights cancelled because it's too hot for planes - BBC News
That is higher than the operating temperature of some planes.
American Airlines announced it was cancelling dozens of flights scheduled to take off from Sky Harbor airport during the hottest part of the day.
The local Fox News affiliate in Phoenix said the cancellations mostly affected regional flights on the smaller Bombardier CRJ airliners, which have a maximum operating temperature of about 118F (48C).
The all-time record for temperatures in Phoenix is just slightly higher, at 122F, which hit on 26 June 1990.
Phoenix flights cancelled because it's too hot for planes - BBC News