macOS detects location but doesn't Set Time Zone Automatically
This just happened to me on High Sierra. Kept trying to change so that the Mac's location would automatically update the timezone. The Mac could detect where is was (both using the Maps application and the red pin in System Preferences / Date &amp; Time / Time Zone showed the correct location) but the time zone was 'stuck' in the place where I was last week. This continued through reboots and toggling all the options in Date &amp; Time.

Here was the fix for me. In Bash (ie, launch Terminal):

$ cd /etc
$ ls -l localt*


It should be a link to the IANA timezone database like so (assuming this Mac is near LA):

lrwxr-xr-x  1 root  wheel  45 Aug 30 17:32 localtime -&gt; /var/db/timezone/zoneinfo/America/Los_Angeles


If it is not:


Turn off the automatic time zone in System Preferences / Date &amp; Time / Time Zone
In Terminal sudo rm /etc/localtime to remove the incorrect link
Reboot (localtime will be recreated)
Restart automatic time zone in System Preferences / Date &amp; Time / Time Zone


That worked for me after Googling and pulling hair for a few minutes. YMMV.