This INTEGER is the lowest 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. A min sitting close to the average, such as 50, suggests stable conditions for this zone, whereas a min far below the average is worth cross-checking against the suspect flag for a possible sensor glitch.