This INTEGER is the highest temperature, in degrees Celsius, that the rear-of-module exhaust sensor recorded during the statistics-collection interval. Because a hot rear-zone reading paired with normal fan speeds elsewhere often points to the chassis's exhaust path itself being blocked, for example by cabling stacked too close to the rear of the rack, an admin diagnosing a SIOC cooling problem checks this specific zone rather than relying only on the SIOC's single roll-up thermal status flag. If the interval's max reads 82 while the current instantaneous reading has settled back near 50, that tells an admin the module hit a brief thermal spike that has since subsided rather than one still ongoing.