Adding Time Zones

To add or edit the time zone data, edit the file wclocktz.ini (see Where is the wclocktz.ini file below).

Note: Exit the Wclock program and start it again after making changes.

To specify a new time zone you need to specify a POSIX.1 TZ string. The full details are specified in POSIX 1003.1 section 8.3. You must use the full expanded format; namely:


An entry for a location that has daylight saving looks like:


For a location that does not have daylight saving, an entry looks like:


Caution: edit this file at your own risk. We have provided some TZ values that we believe are correct but we offer no guarantees on their validity.

It's up to you to derive the correct POSIX.1 TZ string for any new time zones you want to add. If the politicians in the zone in question mess around with the timing of daylight saving every year, you will have to edit the file to suit every year, too. The EU and the USA seem to have reached a consistent standard on daylight saving, as have most parts of Australia. Countries like Israel will need to be edited every year.

For more details, see Explanation of TZ strings.

Note that Wclock does not use the Olson time zone database, although we derived the code that handles the TZ strings from his publicly-available code.

Where is the wclocktz.ini file?

The wclocktz.ini file should be in the Wclock subdirectory of your personal %APPDATA% folder, as follows:

Windows Vista/7/8/10/11
C:\Documents and Settings\<username>\Application Data\Wclock
C:\Windows\Application Data\Wclock

To find the TZ info file's location on your system, use the Check for Updates option on the menu.

To find %APPDATA% on your system, type echo %APPDATA% in a command-line console window (MS-DOS prompt on W98).

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