Question

When getting the time via PHP script (time()), during Daylight Savings Time it seems to return a time value that is one hour off. Is there any way to get the correct time, accounting for Daylight Savings Time?

Answer 1

time() returns a Unix timestamp and a Unix timestamp is a fixed period of time: number of seconds since the Unix Epoch. It isn’t affected by time zones.

Once you have the precise moment, you may want to calculate the local time in a given place:

<?php

$now = time();
echo $now . PHP_EOL;

date_default_timezone_set('Europe/Madrid');
echo date('r', $now) . PHP_EOL;

date_default_timezone_set('Asia/Tokyo');
echo date('r', $now) . PHP_EOL;

… will print different local dates for the same timestamp:

1313683738
Thu, 18 Aug 2011 18:08:58 +0200
Fri, 19 Aug 2011 01:08:58 +0900

The same reasoning applies for the opposite operation:

<?php

date_default_timezone_set('Europe/Madrid');
$then = mktime(23, 55, 30, 12, 31, 2000);
echo $then . PHP_EOL;

date_default_timezone_set('Asia/Tokyo');
$then = mktime(23, 55, 30, 12, 31, 2000);
echo $then . PHP_EOL;

… will print different timestamps:

978303330
978274530