Install ntpd either from pacman or the Add remove software.
I.E. in terminal pacman -U ntpd or search for and install from the Add Remove GUI.
Then in Autostart, (Session and Startup) add a new entry and in the command line put
It will then go to the internet and set your clock.
Antergos does not seem to get the timezone UTC offset.
I trust internet time, and this seems to take care of it easily.
You can also just run this in terminal, but I just set it to that autostart as it is normally online on my desktop.
If your in a WiFi world you can create a desktop launcher to do the same, or put a sleep 30 ntpd -gg
instead to allow time for WiFi to make the connection.
Now if your running Windows 7 or later, it has already got automatic internet time setting, but I find you have to change the reference to nist.gov as the default one always seems to fail.
I was going nuts to get Antergos to display the correct time.
I am hoping a time setting gadget will get added to the system settings panel someday. Until then this is a workaround.