The default Timezone (tz) for users who have not specified a custom offset may be configured manually.
Primary Method
- Create a backup copy of the LocalSettings.php file found in your install directory
 - Edit LocalSettings.php and add the following code:
 
#Set Default Timezone
$wgLocaltimezone = "America/Los_Angeles";
$oldtz = getenv("TZ");
putenv("TZ=$wgLocaltimezone");
$wgLocalTZoffset = date("Z") / 3600;
putenv("TZ=$oldtz");
- Set the '$wgLocaltimezone' value to the proper value which you can find here. See examples below.
 
$wgLocaltimezone = "Europe/London"; $wgLocaltimezone = "Asia/Taipei";
Note: This timezone will be used in:
- ~~~~ signatures
 - timestamps in recentchanges
 - timestamps in history
 
Note: Upload and deletion logs will probably still be listed in UTC
Note: This method has been confirmed to work on MediaWiki: 1.5.6.
Unconfirmed Methods
- If you just want to use the local time of your PC, you can just add this line in your LocalSettings.php:
 
$wgLocalTZoffset = date("Z") / 3600;
- To use your local time zone (say NZDT) put this in LocalSettings.php
 
$wgLocalTZoffset = 13;
- In my case the primary method did not take daylight savings time into account. The next example works for me:
 
#Set Default Timezone
$wgLocaltimezone = "Europe/Amsterdam";
#Calculate the timezone offset with UTC
$oldtz = getenv("TZ");
putenv("TZ=$wgLocaltimezone");
$wgLocalTZoffset = date("Z") / 3600   Date("I");
putenv("TZ=$oldtz");
Note: The methods in this section are unconfirmed and may not work properly.