date_default_timezone_set() function to set default time zone of server

Irrespective of time zone set in php.ini file , we can set the time zone of the server for our script by using date_default_timezone_set() function.
The list of applicable time zone identifier is available here.
Here is the sample code to set the time zone.

<?Php
echo date_default_timezone_set();
?>

We can set it like this

date_default_timezone_set('America/Chicago');

After setting the time zone , you can read the same by using date_default_timezone_get() function.

Setting the time zone in php.ini file

You can set the default time zone at php.ini file. If you are using for first time then search for the line saying

;date.timezone =

Change it to

date.timezone ="Asia/Calcutta";

You can change the area as per your requirement by using time zone identifier .

Example: Dynamically Switching Time Zones

date_default_timezone_set('America/New_York');
echo date('Y-m-d H:i:s').'<br>'; // Output: Current time in New York
date_default_timezone_set('Asia/Kolkata');
echo date('Y-m-d H:i:s'); // Output: Current time in Kolkata

Output

2025-11-20 23:59:42
2025-11-21 10:29:42

Example: Listing All Available Time Zones

$timezones = timezone_identifiers_list();
print_r($timezones);

Or to display as list

$timezones = timezone_identifiers_list();
foreach($timezones as $key=>$value){
	echo "$key : $value".'<br>';
}

Creating a dropdown list for user selection of Timezone

PHP Date Functions date_default_timezone_get() get the time zone

Subhendu Mohapatra

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