The sensor is located on the case (not near the exhaust) of the server. With the structure of my appartment this is the only place I can realistically put my Server but sadly also the hottest place in my appartment.
The outside temperature is supposed to reach 36°C today so I expect the ambient temp for the server to rise another 2-3 degrees.
On the contrary, they found that temperature had almost no bearing on failure rate.
https://static.googleusercontent.com/external_content/untrusted_dlcp/research.google.com/en/us/archive/disk_failures.pdf