Steps to Reproduce
1. Build a building such as a gas pump. 2. Mouse over the "Temperature" link in the "Information" panel. 3. Overheat temperature will be displayed as 348 C. That's the overheat temperature in Kelvin, not Celsius. 348 K is 75 C, which is what should be displayed if you are going to use C.
This issue has not been confirmed by a developer yet.