Marble has been used in sculpture and architecture since Antiquity. When exposed outdoors, it is subjected to physical, chemical, or biological weathering. Studies have shown that some deterioration (bowing, microcrack generation, thermal damage) can result from the exposure to cyclical thermal variations, but the actual temperature range triggering these phenomena remains unknown. Specifically, it is not yet understood if these phenomena are activated at a certain threshold temperature or by prolongated cyclic temperature exposure . In this work, the evolution of the mechanical state of Carrara Gioia marble samples under thermal stress is followed by means of Nonlinear Resonant Ultrasound Spectroscopy (NRUS). The results show, on the one hand, a progressive decrease of the linear parameter (resonant frequency) with heating temperature. This evolution agrees with results from previous works and with the consequent evolution of the microstructure. The (nonclassical) nonlinear parameter, on the other hand, exhibits an increase in the mild temperature range (40 -85°C), followed by a decrease for the highest temperatures (85 -250°C). This evolution of the NRUS parameters, as well as microstructural observations, depicts mild temperature induced degradation in Carrara marble. Carrara marble decohesion starts at the mesoscopic scale as evidenced by the initial increase in the nonlinear parameter, and then progressively expands to the macroscopic scale as highlighted by the resonant frequency evolution.