How do I get midnight of current day in a specified timezone in PHP?

Question

I have a server in New York, and a "client" in California which expects that server to figure out midnight of the current day in California, which is not the same as New York's for three hours out of the day.

I have only been able to calculate midnight for the current day as is seen by New York, but I need to be able to calculate midnight of the current day for California (or any other arbitrary timezone)

I do have access to the timezone's offset from UTC.

$tzOffset = "-700"; // Timezone offset from UTC (in this case, PDT)

The (semi-working) method that I'm using right now is

strtotime("00:00:00 " . $tzOffset);

On Jun 25 at 10:00 PM PDT, this method is returning Jun 26 at 12:00 AM PDT as midnight, when it should be returning Jun 25 12:00 AM PDT.

Answer 1

// create time from string
$date_time = new Datetime('midnight', new Datetimezone('America/Los_Angeles'));
// string representation of time in America/Los_Angeles
echo $date_time->format('Y-m-d H:i:s') . PHP_EOL;
$date_time->setTimezone(new Datetimezone('America/New_York'));
// string representation of the same time in America/New_York
echo $date_time->format('Y-m-d H:i:s') . PHP_EOL;

http://php.net/manual/en/datetime.formats.php