Air is less dense and generates less lift in extreme heat, making it harder for airplanes to take off, according to the FAA. In some cases, airlines must reduce the amount of cargo and/or passengers on the plane in order to take off in high-heat conditions.

Yes, planes can fly in 90°F (32°C) weather without any major issues, but heat significantly impacts aircraft performance. As air temperature rises, the air becomes less dense (a concept called "high density altitude"). Thinner air means the wings produce less lift and the engines produce less thrust. Consequently, in 90-degree weather, a plane requires a longer takeoff roll to reach the necessary speed for liftoff and has a slower climb rate. On extremely hot days (usually 110°F or higher), airlines may have to implement "weight restrictions," which involves leaving behind passengers, cargo, or fuel to ensure the plane is light enough to take off safely from a specific runway. While 90 degrees is well within the operating limits of any commercial jet—which routinely take off from desert cities like Dubai or Phoenix—pilots and dispatchers must carefully calculate performance charts to adjust for the reduced air density, ensuring they have enough runway to clear obstacles at the end of the airfield.