Macbook Pro Retina 15'' - High CPU temperature I've seen a few similar questions on here but none seem to have a good answer, nor seeing the temperature levels I'm seeing. 

Notebook is only a month old and just installed iStat Menus and noticed that the "CPU Die - Digital" sensor temperature is consistently over 80℃.

Currently it is 96℃ with the CPU at 85% idle, all load averages of 2.3.

The lowest I've managed to get it is 49℃ by killing almost everything running. The highest is 103℃, by booting multiple virtual machines. From what I've read, this is 2℃ off the shutdown temperature for the CPUs… and the fans were only running at 3800/4000.

So, is this normal? Have I got a dud MacBook or is iStat Menus to blame?
Can't seem to find out how to read the sensors via command line.
Lets me try to help you to understand what is going on here:

Any third party software uses the already available information from your Mac as designed by Apple that uses thermal diodes attached to different points in the system. Apple has done a lots of work to correctly manage the thermal load already.

The coding and the mathematics to covert the given information correctly in to the Temperature readings outputs by third party software could be tricky, so use it with grain of slat, since it varies a lot from Hardware (diode) + EFI + CPU types from system to system. In English, the third party software's are not always calibrated for your specific system.

Note from Intel:


  Intel® Processors have built-in thermal protection. If the processor
  gets too hot, the built-in protection shuts down the computer. If your
  computer is not over-clocked and is running under the design
  specifications, the built-protection can help prevent damage to your
  system.


High Temperature readings:

If you use a third party software to measure the temperature or the Extensible Firmware Interface (EFI) readings, contact the software vendor to ensure the software is validated to work with your processor. 

If you still want to know more or you see weird Temperature reading, please go to Intel web site and look for your specific CPU specifications. It can not be hotter outside then inside since the CPU is the source of heat, otherwise your computer will just shut down initiated by Intel's CPU internal protection. 

However, if that happens (the shutdown by the CPU), then you need to repair your cooling system (fans + heatsinks ect.)

So I just looked up at Intel for my Intel Core i5 (1.8 Ghz)
and it shows Maximum temp to be 105 Degree Celsius and it has the build in thermal protection.