Effect of ambient temperature on brushless motor

[tungym]

I found an odd phenomenon. I am happy with flying my Hurriane on Align 600L @7s A123. At ambient temp of 29, I can continuous flying with the motor stator core temp of 75 deg C.

Today the ambient temps rised to 35deg C. After 2-3 flights, the motor core is 90deg C! I wait for 10 mins before the next flight (till core lowers to 60 degC) and the result is the same.

The rise in 6 degC ambient temp. results in doubling the rise of the motor temperture (15deg C) !

Any similar experience here?

[BlenderPilot]

What you forgot is the air is getting thinner with higher temperature, thus, your motor has to give more power for the blades slapping that thinner air for the same lifting force.