on MacOS its simple (OsX > select “set time and date automatically” in the date and time system preferences..). if your timezone is set properly it should “just work”

a bit more simple on GNU/Linux/other-n*x. just run 'ntpdate <time-server-address>' but you might need to set the locale and tzinfo.

BE ntp2.belbone.be (195.13.1.153) 
Location: Brussels, Belgium 
Synchronization: xntpd (stratum 2), linux/unix 
Service Area: European Union 
Access Policy: open access 
Contact: Belbone NOC (timemaster@belbone.be)
FR ntp1.curie.fr 
Location: Institut Curie, Section de Recherche, Paris, France. 
Synchronization: Coetanian TSS100 NTP V3 GPS 
Service area: all areas. 
Access policy: Universities, academic research centers, non-profit org ONLY. 
Contact: ntp-adm@curie.fr 
Note: use DNS for IP address 
KR time.nuri.net[203.255.112.4] 
Location: Inet, Inc., Seoul, Korea 
Geographic Coordinates: 37:29:52N, 127:02:15E 
Synchronization: NTP V3 secondary (stratum 2), Sun-SS20/Solaris 2.6 
Service Area: Korea, Japan, Hong Kong / East Asia 
Access policy: open access 
Contact: ntp-admin@nuri.net 
Note: IP addresses are subject to change; please use DNS 
SI biofiz.mf.uni-lj.si (193.2.69.10) 
Location: Institute of Biophysics, University of Ljubljana, Slovenia 
Geographic Coordinates: 46:03:09N, 14:30:40E 
Synchronization: NTP V4 secondary (stratum 2), IBM/Linux 
Service Area: Slovenia/Europe 
Access Policy: open access, please send a message to notify 
Contact: Primoz Peterlin (time@biofiz.mf.uni-lj.si) 
UK ntp2b.mcc.ac.uk (130.88.200.98) 
Location: University of Manchester, Manchester, England 
Synchronization: NTP secondary (S2), PC/FreeBSD 
Service Area: UK 
Access Policy: Open Access 
Contact(s): timelords@mcc.ac.uk 
Note: Please use DNS for address, subject to change