PHP Function: Get timezone offset between two timezones in hours

getTimezoneOffset.php

function getTimezoneOffset(string $timezone1, string $timezone2): int {
  $dateTimezone1 = new DateTimeZone($timezone1);
  $dateTimezone2 = new DateTimeZone($timezone2);
  $timezoneOffset1 = (new DateTime('now', $dateTimezone1))->getOffset();
  $timezoneOffset2 = (new DateTime('now', $dateTimezone2))->getOffset();
  return ($timezoneOffset2 - $timezoneOffset1) / 3600;
}

getTimezoneOffset('America/Chicago', 'America/New_York'); // will return 1
getTimezoneOffset('America/Chicago', 'America/Los_Angeles'); // will return -2