- date_default_timezone_set: documentation ( source)
<?php
date_default_timezone_set("Asia/Tehran");
for ($y = 2000; $y <= 2018; $y++) {
echo $y, ": ", (new DateTime("{$y}-03-22 01:00:00"))->diff(new DateTime("{$y}-03-23 01:00:00"))->format("%a d %h h %i m %s s\n");
}