date_default_timezone_get
date_format
Date/Time
PHP Manual

# date_default_timezone_set

(PHP 5 >= 5.1.0)

date_default_timezone_set — Sets the default timezone used by all date/time functions in a script

### Description

bool date_default_timezone_set ( string `$timezone_identifier` )

date_default_timezone_set() sets the default timezone used by all date/time functions.

> Note: Since PHP 5.1.0 (when the date/time functions were rewritten), every call to a date/time function will generate a `E_NOTICE` if the timezone isn't valid, and/or a `E_STRICT` message if using the system settings or the TZ environment variable.

Instead of using this function to set the default timezone in your script, you can also use the INI setting date.timezone to set the default timezone.

### Parameters

`timezone_identifier`

  The timezone identifier, like UTC or Europe/Lisbon. The list of valid identifiers is available in the List of Supported Timezones.

### Return Values

This function returns `FALSE` if the `timezone_identifier` isn't valid, or `TRUE` otherwise.

### ChangeLog

Version | Description
--- | ---
5.1.2 | The function started to validate the `timezone_identifier` parameter.

### See Also

- date_default_timezone_get()

date_default_timezone_get
date_format
Date/Time
PHP Manual