Change UTC0 to UTC +1/+2 - php

Question

I got a timestamp from my SQL-database: $DBdata = '2019-10-10 12:25:59', this date is UTC+0. Well i live in Denmark where we have the following UTC.
Central EU time winter (UTC+1)
Central EU summertime (UTC+2)
These UTC's changes from summer to winter different dates each year.
Summer time
• 2019 - The night between Saturday 30 March and Sunday 31 March
• 2020 - The night between Saturday 28 March and Sunday 29 March
• 2021 - The night between Saturday, March 27 and Sunday, March 28
• 2022 - The night between Saturday 26 March and Sunday 27 March
• 2023 - The night between Saturday, March 25 and Sunday, March 26
Winter time
• 2019 - The night between Saturday, October 26 and Sunday, October 27
• 2020 - The night between Saturday, October 24 and Sunday, October 25
• 2021 - The night between Saturday, October 30 and Sunday, October 31
• 2022 - The night between Saturday 29 October and Sunday 30 October
• 2023 - The night between Saturday 28 October and Sunday 29 October
Would it be possible to make an if-statement that changes these UTC's, with the right +1/+2?
Maybe something like this:
$Winter= gmdate('Y-m-d H:i:s', strtotime("WinterUTC"));
$Summer= gmdate('Y-m-d H:i:s', strtotime("SummerUTC"));
if (($$DBdata>= $Winter) && ($$DBdata<= $Summer)){
$gmt_dateWinter = gmdate('Y-m-d H:i:s', strtotime($date + '+ 2 hours') );
}else{
$gmt_dateSummer = gmdate('Y-m-d H:i:s', strtotime($date + '+ 1 hours') );
}
I don't know if this even is a smart way to do this. If there is another more smart way to do it please lead me in another direction.
Thanks!

Answer 1

With the DateTime class you can easy convert a date/time to any other time zone.
function convertTimeZone($strDateTime, $sourceTimeZone, $targetTimeZone){
return date_create($strDateTime, new DateTimeZone($sourceTimeZone))
->setTimeZone(new DateTimeZone($targetTimeZone))
->format('Y-m-d H:i:s');
}
example with a daylight saving time
$localTime = convertTimeZone('2019-10-10 12:25:59', 'UTC', 'Europe/Copenhagen');
echo $localTime."<br>";
returns:
2019-10-10 14:25:59
example wintertime
$localTime = convertTimeZone('2019-02-10 12:25:59', 'UTC', 'Europe/Copenhagen');
echo $localTime."<br>";
returns:
2019-02-10 13:25:59
Note: Solutions based on stringtotime are not recommended because of known issues and limitations on some systems.

Answer 2

You can use gmdate and date("I") to generate the date considering the timezone:
gmdate: Format a GMT/UTC date/time
$DBdata = '2019-10-10 12:25:59';
$timezone = +2; // (GMT +2:00) CEST (European Summer Time)
$GMdate = gmdate("Y-m-d H:i:s", strtotime($DBdata) + 3600*($timezone + date("I")));
echo $GMdate;
returns:
2019-10-10 22:25:59
From the date documentation:
I (capital i) Whether or not the date is in daylight saving time: 1
if Daylight Saving Time, 0 otherwise.

Answer 3

Thats simple change in php script default timezone and then display time:
https://www.php.net/manual/en/function.date-default-timezone-set.php
$time = date('H:i:s', time());
$ok = date_default_timezone_set('America/Los_Angeles');
echo $tz = date_default_timezone_get();
$h = new DateTime();
echo $h->format('H:i:s'); // curr time
$o = new DateTime($time);
echo $o->format('H:i:s'); // time