I have recently bought a new NUC - Intel i3 NUC (5 Gen) with 4GB RAM and a hybrid HDD, running Windows 7 Pro (x64)

I have found posts dated 2013 about overheating, but these were about previous generations of NUCs.

SpeedFan shows a System temperature of 67°C (at idle).

The CPU temp is a cool 36°C (at idle).
The case is barely warm to the touch.

Do I have a problem, or am I just being paranoid?
Is there anything I can do to improve cooling in a fanless case?