Run 'date'. If time zone is not correct, then:

Debian / Ubuntu / Devuan:

• dpkg-reconfigure tzdata

Others:

• tzselect
• # Note the time zone it produces, then adjust any of the commands below to suit:
• If the "timedatectl" command is provided by the operating system, the recommended way is to execute a command like this:

  timedatectl set-timezone Europe/London

• For other cases, then execute a command like this one:

  cp /usr/share/zoneinfo/Europe/London /etc/localtime

• # Take note that in some systems /etc/localtime is a symbolic link, then be sure that it points to the correct time zone file.