在PHP中将UTC转换为CST

Question

I want to convert a UTC time to CST using PHP. After googling I got a function

function date_convert($dt, $tz1, $df1, $tz2, $df2) {
  // create DateTime object
  $d = DateTime::createFromFormat($df1, $dt, new DateTimeZone($tz1));
  // convert timezone
  $d->setTimeZone(new DateTimeZone($tz2));
  // convert dateformat
  return $d->format($df2);
}

echo date_convert('2018-05-29 11:44:00', 'UTC', 'Y-m-d H:i:s', 'CST', 'Y-m-d H:i:s');

The output is

2018-05-29 05:44:00

But when I tried converting 2018-05-29 11:44:00 to UTC using online converter, I got the result as 05/29/2018 6:44 AM, which is 1 hour more than what the function returns.

Can anyone help me to find the correct output? Thanks in advance.

Answer 1

I can't explain it, but it only seems to happen with EST/CST, even with changing it to a D.

$n = new DateTime();  // 'date' => '2018-05-29 09:45:01.000000' America/New_York
$n->setTimeZone(new DateTimeZone('UTC')); // 'date' => '2018-05-29 13:45:01.000000'
$n->setTimeZone(new DateTimeZone('EDT')); // 'date' => '2018-05-29 08:45:01.000000'

But if you use a place instead of a timezone, it works well:

$n->setTimeZone(new DateTimeZone('America/New_York'));  // 'date' => '2018-05-29 09:45:37.000000'
$n->setTimeZone(new DateTimeZone('America/Chicago'));  // 'date' => '2018-05-29 08:45:37.000000'

I'd suggest using a place such as America/Chicago instead.