What is the normal operating temperature for the MacBook (2016 generation)?
You can find your processor model by entering the following into a terminal:
sysctl -n machdep.cpu.brand_string

which will return a string, for example, like this:
Intel(R) Core(TM) i5-5287U CPU @ 2.90GHz

You can then search for your processor on the intel product specifications page, by pasting for example i5-5287U into the search box.
On the resulting page you will see something called TJUNCTION ...

This is the maximum temperature recommended for that processor. You can monitor this with htop.