unfortunately I dont own any surface thermometer or such alike...

When clocking my Teensy 3.6 with 180MHz it gets 'quite warm' (I know,
that's not very scientific, sorry). The MCU is still touchable without
hurting oneself but it is quite noticeable and above body temperature.
Its running the WavePlayerUSB (which does not work for me, but that
is another story)...
The SDcard is ok and the files are readable by the Teensy 3.6.

Is this normal? How much is too much?

Thanks for any help in advance!