Torghabe
The CFM 56 7B series are all Flatrated at 30 degree Celsius.
Ie, At sealevel STD but Isa pluss 15 ( 30c) the engine will produce 26300lbs for an CFM 56-7B26 for example.
Any hotter than that and the engine produces LESS pwr at full thrust as it gets any warmer.
I always find it fascinating when when the FO ask " we can assume with 31c "