This work presents, for the first time, the Low Frequency Noise (LFN) of submicron graded-channel (GC) SOI nMOSFETs as a function of temperature in the range from 300 K up to 500 K. The measured GC SOI devices are from a 150 nm commercial technology from OKI Semiconductors. The results were obtained through experimental measurements in a device with channel length (L) of 240 nm, working in linear regime at VDS=50mV. It is shown that the origin of the noise changes from carrier number fluctuations to mobility fluctuations as the temperature is increased. Additionally, the generation and recombination noise plays a significant role on the overall noise with the temperature rise.