How to set the timezone in Plesk and enable its Synchronization?

Applicable to:

Using Plesk Interface

Log into Plesk;
Go to Tools & Settings > System Time;
Set the correct time zone for the server;
Enable the Synchronize system time option and specify the NTP server domain name or its IP address;
Click OK.

Using the command line interface

Connect to the server through SSH;
Set the correct timezone for your server, for example:

# plesk sbin timemng --set-timezone --timezone=America/Sao_Paulo

The list of timezone names is available here:
List of Supported Timezones
Set NTP server synchronization as a crontask:

# plesk sbin timemng --set-sync-time --time-server=pool.ntp.org
Enable the NTP synchronization:

# plesk db "replace into misc(param,val) values ('ntp_enabled','true');"
Set pool.ntp.org as the server to sync server time:

# plesk db "replace into misc(param,val) values ('ntp_server','pool.ntp.org');"
Restart Plesk-managed server for the time zone change takes effect:

# service sw-engine restart