Manual:Timezone

The default Timezone (tz) for users who have not specified a custom offset may be configured manually.

Default value

The default value is taken from the webserver configuration (PHP ini file). For documentation:

https://www.php.net/datetime.configuration#ini.date.timezone

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 = "Asia/Jakarta";
date_default_timezone_set( $wgLocaltimezone );

Set the $wgLocaltimezone value to the proper value which you can find here. See examples below.

$wgLocaltimezone = "UTC";
$wgLocaltimezone = "Europe/London";
$wgLocaltimezone = "Asia/Taipei";

This timezone will be used in:

~~~~ signatures
timestamps in recentchanges
timestamps in history

Adding this code to the LocalSettings.php conflicts with the RSS Feed dates in Extension:RSS. See the Discussion page of Extension:RSS for more information

Alternative method

This method has been confirmed by multiple users in situations where the primary method has not worked.

$wgLocaltimezone = "America/Sao_Paulo";
$dtz = new DateTimeZone($wgLocaltimezone);
$dt = new DateTime('now', $dtz);
$wgLocalTZoffset = $dtz->getOffset($dt) / 60;
unset($dtz);
unset($dt);

Alternative methods

If you just want to use the local time of your PC, you can add this line in your LocalSettings.php. This method is what MediaWiki does by default (see includes/Setup.php); it also avoids problems with daylight savings time:

$wgLocalTZoffset = date("Z") / 60;

Unconfirmed methods

To use your local time zone (say NZDT) put this in LocalSettings.php

$wgLocalTZoffset = 13 * 60;

This example may also work

$wgLocaltimezone="Europe/Berlin";
$wgLocalTZoffset = +120;

In this case the primary method did not take daylight savings time into account. The example below works:

#Set Default Timezone
$wgLocaltimezone = "Europe/Amsterdam";

#Calculate the timezone offset with UTC
$oldtz = getenv("TZ");
putenv("TZ=$wgLocaltimezone");
$wgLocalTZoffset = date("Z") / 60 + date("I") * 60;
putenv("TZ=$oldtz");

To make it work in 1.5.8, specify the offset in hours, so change all occurrences of '/ 60' to '/ 3600', for example.

$wgLocaltimezone = "Europe/Amsterdam";
#Calculate the timezone offset with UTC
$oldtz = getenv("TZ");
putenv("TZ=$wgLocaltimezone");
$wgLocalTZoffset = date("Z") / 3600;
putenv("TZ=$oldtz");

Combine it with the tip above to make daylight savings work.

This line is needed in 1.16. It applies to both anonymous and logged in users. Note that you will need to provide the correct values if you want the zone to be selected by default in the timezone dropdown:

$wgDefaultUserOptions['timecorrection'] = 'ZoneInfo|' . (date("I") ? 120 : 60) . '|Europe/Berlin';

The methods in this section are unconfirmed and may not work properly.

Manual timezone specification

The primary method needs the server to support the 'tz' database; some non-GNU hosts don't do that. However you can supply timezone data manually - unfortunately, only "GMT0" seems to work on Windows.

E.g. use

$wgLocaltimezone = "CET-1CEST-2,M3.5.0/2,M10.5.0/2";

instead of

$wgLocaltimezone = "Europe/Budapest";

or

$wgLocaltimezone = "AEST-9,M10.5.0/3,M4.1.0/3";

instead of

$wgLocaltimezone = "Australia/Sydney";

For details see

System configuration: Time Zones (List of time zones)
Specifying the Time Zone with TZ (general format)
timezones.conf.xml (another list of time zones)