date_default_timezone_set

(PHP 5 >= 5.1.0)

date_default_timezone_set Устанавливает временную зону по умолчанию для всех функций даты/времени в скрипте

Описание

bool date_default_timezone_set ( string $timezone_identifier )

date_default_timezone_set() устанавливает временную зону по умолчанию для всех функций даты/времени в скрипте .

Замечание:

Начиная с версии PHP 5.1.0 (когда функции даты/времени были переписаны), вызов любой функции даты времени генерирует E_NOTICE, если временная зона имеет неверное значение, и/или E_WARNING, если используются системные параметры или переменная окружения TZ.

Вместо использования этой функции, Вы можете воспользоваться INI настройкой date.timezone для установки временной зоны по умолчанию.

Список параметров

timezone_identifier

Идентификатор временной зоны, как например UTC или Europe/Lisbon. Список поддерживаемых временных зон.

Возвращаемые значения

Функция возвращает FALSE, если timezone_identifier имеет неверное значение, в остальных случаях TRUE.

Примеры

Пример #1 Получение временной зоны по умолчанию

<?php
date_default_timezone_set
('America/Los_Angeles');

$script_tz date_default_timezone_get();

if (
strcmp($script_tzini_get('date.timezone'))){
    echo 
'Временная зона скрипта отличается от заданной в INI-файле.';
} else {
    echo 
'Временные зоны скрипта и настройки INI-файла совпадают.';
}
?>

Список изменений

Версия Описание
5.3.0 Теперь выбрасывает E_WARNING вместо E_STRICT.
5.1.2 Функция начала проверять timezone_identifier.

Смотрите также

Коментарии

Note that there may be some unexpected side-effects that result from using either set_default_timezone() or the putenv("TZ=...") workalike for earlier PHP versions.  ANY date formatted and output either by PHP or its apache host process will be unconditionally expressed in that timezone.

[red. That is only true for the putenv() hack - Derick]

This does indeed include the web server's logs and other output files and reports which by default usually do not include any indication of timezone. This has a further side-effect on log processing and analysis, obviously.
2006-12-21 19:27:03
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
The problem:

date() [function.date]: It is not safe to rely on the system's timezone settings. Please use the date.timezone setting, the TZ environment variable or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/Los_Angeles' for 'PST/-8.0/no DST' instead

Of course this is a problem that recently surfaced since PHP5. Quick fix is to set your time zone, add this line to your php code:

date_default_timezone_set("America/Los_Angeles");
2007-02-12 06:21:36
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
If you want users to choose their own timezones, here's some code that gets all available timezones but only uses one city for each possible value:

<?php

$timezones 
DateTimeZone::listAbbreviations();

$cities = array();
foreach( 
$timezones as $key => $zones )
{
    foreach( 
$zones as $id => $zone )
    {
       
/**
         * Only get timezones explicitely not part of "Others".
         * @see timezones.others
         */
       
if ( preg_match'/^(America|Antartica|Arctic|Asia|Atlantic|Europe|Indian|Pacific)\//'$zone['timezone_id'] ) )
           
$cities[$zone['timezone_id']][] = $key;
    }
}

// For each city, have a comma separated list of all possible timezones for that city.
foreach( $cities as $key => $value )
   
$cities[$key] = join', '$value);

// Only keep one city (the first and also most important) for each set of possibilities. 
$cities array_unique$cities );

// Sort by area/city name.
ksort$cities );

?>
2008-07-15 04:46:56
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
While it's easy to change timezones based on names or abbreviations, I haven't found any straightforward way of doing so using an offset integer.  This situation comes up if you're using AJAX to get information about a user's timezone; javascript's getTimezoneOffset() method just sends you an offset number. So, here's my clunky solution: an adaptation of chris' function at http://us.php.net/manual/en/function.timezone-name-from-abbr.php.

<?php
   
function set_tz_by_offset($offset) {
       
$offset $offset*60*60;
       
$abbrarray timezone_abbreviations_list();
        foreach (
$abbrarray as $abbr) {
           
//echo $abbr."<br>";
               
foreach ($abbr as $city) {
                   
//echo $city['offset']." $offset<br>";
                       
if ($city['offset'] == $offset) { // remember to multiply $offset by -1 if you're getting it from js
                               
date_default_timezone_set($city['timezone_id']);
                               return 
true;
                        }
                }
        }
   
date_default_timezone_set("ust");
       return 
false;
       }

set_tz_by_offset(-1);

?>

[EDIT BY thiago AT php DOT net: This code has contributions from iateadonut at gmail dot com]
2008-11-11 22:29:01
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Timezone using other approaches:
<?php $datetime strtotime($originaldatetime) + $time;
$datetime date('M d, Y h:i A'$datetime);?>

$time obtained from table below:
-25200|International Date Line (West) GMT-12|
-21600|Midway Island, Samoa GMT-11|
-18000|Hawaii, Honolulu GMT-10|
-14400|Alaska GMT-9|
-10800|Pacific Standard Time, US, Canada GMT-8|
-7200|British Columbia N.E., Santa Fe, Mountain Time GMT-7|
-3600|Central America, Chicago, Guatamala, Mexico City GMT-6|
0|US, Canada, Bogota, Boston, New York GMT-5|
+3600|Canada, Santiago, Atlantic Standard Time GMT-4|
+7200|Brazilia, Buenos Aires, Georgetown, Greenland GMT-3|
+10800|Mid-Atlantic GMT-2|
+14400|Azores, Cape Verde Is., Western Africa Time GMT-1|
+18000|London, Iceland, Ireland, Morocco, Portugal GMT|
+21600|Amsterdam, Berlin, Bern, Madrid, Paris, Rome, GMT+1|
+25200|Athens, Cairo, Cape Town, Finland, Greece, Israel GMT+2|
+28800|Ankara, Aden, Baghdad, Beruit, Kuwait, Moscow GMT+3|
+32400|Abu Dhabi, Baku, Kabul, Tehran, Tbilisi, Volgograd GMT+4|
+36000|Calcutta, Colombo, Islamabad, Madras, New Dehli GMT+5|
+39600|Almaty, Dhakar, Kathmandu, Colombo, Sri Lanka GMT+6|
+43200|Bangkok, Hanoi, Jakarta, Phnom Penh, Australia GMT+7|
+46800|Taipei, Beijing, Hong Kong, Singapore, GMT+8|
+50400|Seoul, Tokyo, Central Australia GMT+9|
+54000|Brisbane, Canberra, Guam, Melbourne, Sydney, GMT+10|
+57600|Magadan, New Caledonia, Solomon Is. GMT+11|
+61200|Auckland, Fiji, Kamchatka, Marshall, Wellington, GMT+12|
2008-12-03 01:13:13
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
I experienced that using this function highly increases performance of functions like getdate() or date() using PHP 5.2.6 on Windows.
I experienced similar results on Linux servers with PHP 5.2.6 and 5.2.10, although the difference was not that significant on these servers: The PHP 5.2.10 server did run with date_default_timezone_set ("only") twice as fast as without. The 5.2.6 server did 5 times faster with date_default_timezone_set. As you can see below, the 5.2.6-Windows machine did a LOT faster.
Of course these machines have completely different hardware and can not really be compared, but all show improved performance.

I checked PHP 4.4.9 on Windows (without date_default_timezone_set of course) and noticed that its as fast as PHP 5.2.6 with date_default_timezone_set.

The following script shows this:

<?php

# uncomment to see difference
# date_default_timezone_set(date_default_timezone_get());

function getmicrotime()
 {
 list(
$usec$sec) = explode(' ',microtime());
 return (
$sec.substr($usec,1,7));
 }
 
$start=mktime(0,0,0,1,1,2005);
$end=mktime(0,0,0,1,1,2020);
$nr=50000;
 
$start_time=getmicrotime();
for(
$i=0;$i<$nr;$i++) {
# $value=getdate(rand($start,$end));
 
date("H:i:s d.m.Y",rand($start,$end));
}
$end_time=getmicrotime();

echo 
"Time: ".($end_time-$start_time);

// With date_default_timezone_set(): "Time: 0.379343986511"
// Without date_default_timezone_set(): "Time: 7.4971370697"

?>

Note that the timezone is not changed, it is only set again. I really wonder why this makes such a big performance difference, but its good to know.
2010-01-09 09:52:21
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
It's really a hassle that there is no way to set the timezone offset. I attempted to use the code that searched for the correct timezone name by offset from below. I found it didn't work reliably since various cities may have different rules about time DST etc. My solution is to actually search the array and do a test to insure the offset is what I expect it to be. It seems very kludgey (if thats a word) but it works. 

<?php
function setTimezoneByOffset($offset
    {
     
$testTimestamp time();
       
date_default_timezone_set('UTC');
       
$testLocaltime localtime($testTimestamp,true);
       
$testHour $testLocaltime['tm_hour'];       

     
   
$abbrarray timezone_abbreviations_list();
    foreach (
$abbrarray as $abbr
    {
       
//echo $abbr."<br>";
     
foreach ($abbr as $city
      {
               
date_default_timezone_set($city['timezone_id']);
               
$testLocaltime     localtime($testTimestamp,true);
               
$hour                     $testLocaltime['tm_hour'];       
               
$testOffset $hour $testHour;
                if(
$testOffset == $offset)
                {
                    return 
true;
                }
      }
    }
    return 
false;
    }
?>
2010-03-04 10:54:40
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
This is a good script if you know or control your system so that you know that the local TZ in your OS is correct. Unfortunately, this script still creates an warning message under BSD UNIX.

To fix this, just add an "@" in front of "localtime" as:

$arr = @localtime($iTime);
2010-09-11 09:22:54
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Most of the scripts here depend on PHP identifying the correct zone when one is not set, but that does not always happen. 

For example PHP 5.3.3 gives a 'UTC' result for a detected '8.0/no DST'. Not much help.

So for those of us who for very good reasons really cannot set time zones in scripts of in .ini files, here is a function 
for use in a Windows environment that sets the default time zone to the OS time zone and returns the detected and set texts.

<?php
function date_system_timezone_set(){
 
$shell = new COM("WScript.Shell") or die("Requires Windows Scripting Host");
 
$time_bias = -($shell->RegRead(
"HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control
\\TimeZoneInformation\\Bias"
))/60;
 
$ab = -($shell->RegRead(
"HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control
\\TimeZoneInformation\\ActiveTimeBias"
))/60;
 
$sc $shell->RegRead(
"HKEY_USERS\\.DEFAULT\\Control Panel\\International\\sCountry");
  foreach(
timezone_abbreviations_list() as $tza) foreach($tza as $entry){
   
$country strtok($entry['timezone_id'],'/');
   
$locale strtok('|');
    if(
$country==$sc && $ab==($entry['offset']/60/60) && ($ds $time_bias!=$ab)==$entry['dst']){
     
date_default_timezone_set($timezone_identifier $country."/".$locale);
      return 
sprintf('%.1f',$ab)."/".($ds?'':'no ').'DST'." ".$timezone_identifier;
     }
   }
  return 
false
 }
?>
2010-10-11 04:35:20
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
People complaining that there's no way to set the offset - you are wrong. You can easily set the offset from GMT (see "Other" in available zones). And since all zones are offset from GMT it's just easy math with + or - to get that. So if you i.e. want the offset not from GMT but your timezone, then compute offset of your zone from GMT (say if you in Berlin its +1 now (mind summer time!)) and then offset for your target zone (i.e NYC is -5) then sum abs! of these values and set the sign of bigger (abs) value -> total offset from your european zone to NYC is then abs(-5)+abs(1) = 6 and set "-" as NYC zone absolute value is bigger. So whatever time is in Berlin, in NYC it's 6hrs earlier. But it's better to do two step calculation and calculate always from GMT
2010-11-20 15:58:56
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
After poundering and knocking my head on the table, I finally got a proper fix for Windows and PHP timezone handling.

Since Windows applies the DST to ActiveTimeBias in the registry, you only need this to apply.
The only problem is, that it cant use the timezone_set command.

You can request a response back in any date-format you wish, or use the default one given in the function itself.

<?php

// Return proper time
function time_zone_fix($timeGiven "H:i:s")
{
   
$shell = new COM("WScript.Shell") or die("Requires Windows Scripting Host");
   
$time_bias = -($shell->RegRead("HKEY_LOCAL_MACHINE\\SYSTEM\\
CurrentControlSet\\Control\\TimeZoneInformation\\
ActiveTimeBias"
)) / 60;
   
$timestamp_bias 60 60 $time_bias;
    echo 
$time_bias "<br />";
    return 
gmdate($timeGivenstrtotime($timestamp_bias " seconds"));
}
?>
2011-02-01 10:30:24
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
If you want to set the default timezone to the user's local timezone, you have to combine PHP and JavaScript. Here's how to do it:

<?php
session_start
();
if(!isset(
$_SESSION['timezone']))
{
    if(!isset(
$_REQUEST['offset']))
    {
   
?>
    <script>
    var d = new Date()
    var offset= -d.getTimezoneOffset()/60;
    location.href = "<?php echo $_SERVER['PHP_SELF']; ?>?offset="+offset;
    </script>
    <?php   
   
}
    else
    {
       
$zonelist = array('Kwajalein' => -12.00'Pacific/Midway' => -11.00'Pacific/Honolulu' => -10.00'America/Anchorage' => -9.00'America/Los_Angeles' => -8.00'America/Denver' => -7.00'America/Tegucigalpa' => -6.00'America/New_York' => -5.00'America/Caracas' => -4.30'America/Halifax' => -4.00'America/St_Johns' => -3.30'America/Argentina/Buenos_Aires' => -3.00'America/Sao_Paulo' => -3.00'Atlantic/South_Georgia' => -2.00'Atlantic/Azores' => -1.00'Europe/Dublin' => 0'Europe/Belgrade' => 1.00'Europe/Minsk' => 2.00'Asia/Kuwait' => 3.00'Asia/Tehran' => 3.30'Asia/Muscat' => 4.00'Asia/Yekaterinburg' => 5.00'Asia/Kolkata' => 5.30'Asia/Katmandu' => 5.45'Asia/Dhaka' => 6.00'Asia/Rangoon' => 6.30'Asia/Krasnoyarsk' => 7.00'Asia/Brunei' => 8.00'Asia/Seoul' => 9.00'Australia/Darwin' => 9.30'Australia/Canberra' => 10.00'Asia/Magadan' => 11.00'Pacific/Fiji' => 12.00'Pacific/Tongatapu' => 13.00);
       
$index array_keys($zonelist$_REQUEST['offset']);
       
$_SESSION['timezone'] = $index[0];
    }
}
date_default_timezone_set($_SESSION['timezone']);

//rest of your code goes here
?>
2012-01-28 10:11:24
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
A simple method for conversation between two time zone.

<?php
$date 
= new DateTime("2012-07-05 16:43:21", new DateTimeZone('Europe/Paris'));

date_default_timezone_set('America/New_York');

echo 
date("Y-m-d h:iA"$date->format('U'));

// 2012-07-05 10:43AM
?>
2012-07-06 11:45:52
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
Regarding my post 3 years before:
The performance impact seems to be caused by the fact that a log message is written if you do not set a timezone. And writing a log message to disk can take significantly longer than actually calculating date() or getdate() - esp. on systems with slow IO like the Windows machine I used 3 years ago.

PHP 4 did not produce any log messages, and therefore was as fast as PHP5 with a timezone set.

So if you run date() or getdate() a lot of times, this will cause a lot of log messages to be written to disk (if you did not disable them in your php.ini settings), which will take its time.

So either use this function or set the ini-setting "date.timezone" to make things faster.
(And have a look into your logfiles! Solving all those warnings will not only save you disk space but will also speed up your web application.)
2013-03-09 23:39:40
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
I'm sure I'm not the only one who is distressed by the recent default behavior change to E_NOTICE when the timezone isn't explicitly set in the program or in .ini.  I insure that the clock on the server IS correct, and I don't want to have to set it in two places (the system AND PHP).  So I want to read it from the system.  But PHP won't accept that answer, and insists on a call to this function.  So, here's my answer:

<?php
 
function setTimezone($default) {
   
$timezone "";
   
   
// On many systems (Mac, for instance) "/etc/localtime" is a symlink
    // to the file with the timezone info
   
if (is_link("/etc/localtime")) {
       
       
// If it is, that file's name is actually the "Olsen" format timezone
       
$filename readlink("/etc/localtime");
       
       
$pos strpos($filename"zoneinfo");
        if (
$pos) {
           
// When it is, it's in the "/usr/share/zoneinfo/" folder
           
$timezone substr($filename$pos strlen("zoneinfo/"));
        } else {
           
// If not, bail
           
$timezone $default;
        }
    }
    else {
       
// On other systems, like Ubuntu, there's file with the Olsen time
        // right inside it.
       
$timezone file_get_contents("/etc/timezone");
        if (!
strlen($timezone)) {
           
$timezone $default;
        }
    }
   
date_default_timezone_set($timezone);
 }
?>

Use it by calling it with a fallback default answer.

Yes, I know it doesn't work on Windows.  Neither do I :)  Perhaps someone wants to add that functionality.

Hope this helps someone.
2013-12-11 01:54:25
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
I was having major issues with the date.timezone setting after I updated from 5.3.3 to 5.4.29. I still need to update further, and perhaps it's a bug in this version that will be fixed when I update..

But to fix the issue of php not being about to find my time zone, I added a .htaccess file to the root of my web directory. All I have in it is this one line (without quotes)

"php_value date.timezone America/Denver"

And now the timezone is set in any directory I browse in. Very strange, and I still haven't figured out why It wont work from the php.ini file. But here's how to overcome the frustration.
2014-05-31 00:47:57
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
This creates a huge problem for downloadable programs, which obviously cannot be hardcoded as this suggests, since the coder has no idea where they will be run.

Seems to me that if the server's timezone cannot be relied on, then THAT is the the problem which needs fixed. Not, cause the coder's syntactically-correct work to generate bogus error messages.
2015-01-02 02:04:49
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
I found a need to change the timezone based on a DB record, so it would display properly for each record.  So I wrapped some of the other posts into this small class:

<?php
class TZStack
{
    private 
$stack = array();
    public function 
__construct(){}
    public function 
push($newTZ)
    {
       
array_push($this->stackdate_default_timezone_get());
        if (isset(
$newTZ) && ("" != $newTZ))
        {
           
date_default_timezone_set($newTZ);
        }
    }
    public function 
pop()
    {
        if (
count($this->stack) > 0)
        {
           
date_default_timezone_set(array_pop($this->stack));
        }
    }
}
// the global TZ stack for the rest of the code  to use.
$tzStack = new TZStack();
// In case I need to know the TZ at the web server. :)
$script_tz date_default_timezone_get();
?>

Then in my per-record code:

<?php
   
foreach($records as $item)
    {
       
$tzStack->push($item['TZ']);
       
$TZ date("T"time());
       
// code that displays this record, using $TZ.
       
$tzStack->pop();
    }
?>
2015-04-19 03:10:38
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html
Автор:
I avoid using strings as arguments when a constant or other kind of reference should be used.  For example, to set the default timezone to UTC, the recommended code is:

<?php
date_default_timezone_set
('UTC'); // Potential for mistakes
?>

However, using the string "UTC" here opens up the possibility for mistakes.  For example, if the string "UTX" were entered accidentally,
most PHP editors PHP won't flag that as an error.  When run, the interpreter will show the common warning about a misspelled timezone and using "UTC" by default. 

PHP should define constants to represent the major timezones.  Actually it does, but "DateTimeZone::UTC" inconveniently contains the integer value 1024, not a string.  However, "DateTimeZone::listIdentifiers()" can turn a timezone integer into an array of timezone identifier strings.  So, I use this code:

<?php
date_default_timezone_set
(DateTimeZone::listIdentifiers(DateTimeZone::UTC)[0]);  // Foolproof
?>

It's longer, but if I make a mistake specifying the timezone (which I won't because I use code completion), my editor would highlight the problem. If I ran the program with an invalid timezone reference anyway, PHP would give the more helpful error, "Fatal error: Undefined class constant 'UTX' in /tmp/tarfu.php on line 24".
2017-10-27 17:05:27
http://php5.kiev.ua/manual/ru/function.date-default-timezone-set.html

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