This is the current ambient air temperature, in degrees Celsius, measured by a sensor near this IOM, reflecting the surrounding chassis airflow rather than any internal component's own heat. Because it tracks air temperature rather than a component temperature, a rising value here independent of the card's own tempAvg or procTemp readings usually points to a chassis or rack cooling problem rather than a fault in the IOM itself. For example, an ambientTemp of 41 alongside a recently reported failed fan module in the same chassis would confirm airflow, not the card, is driving the reading up.