Data centers aim at provisioning on-demand processing, storage and networking capabilities in a reliable and scalable way. In this context, proper maintenance of IT equipment within data center (DC) premises is crucial as it ensures prolonged lifetime of servers and uninterrupted availability of resources. This paper focuses on the analysis how the exact temperatures in a real big DC cluster of 10 368 cores correspond to thermal guidelines for IT devices. Available readings of servers exhaust air temperature, inlet air temperature, as well as CPUs temperature have been analyzed to uncover general statistical properties which are subsequently aggregated into several descriptive metrics that reveal global and local trends. The ultimate outcome of this research is the improvement of DC thermal management for sustainable operations via a set of recommendations.