Calculate Central European Summer Time (CEST)

Snippet Code

Countries of the European Union add an hour to the time during summer to better seize sunlight, so for several months GMT 0 becomes GMT +1, GMT+1 becomes GMT-2 and so on. This is known as Central European Summer Time (CEST). This script takes a Unix timestamp and adds an hour to it (3600 seconds) if we are in this summer period.


<?php

/* 

Author: Ignacio Segura "Nachenko", http://www.pensamientosdivergentes.net

*/



function timestamp_cest($t)

{

    $year = strftime("%Y", $t);

    $initDay = (31 - ( floor(5 * $year / 4) + 4) % 7) ; 

    $endDay = (31 - ( floor(5 * $year / 4) + 1) % 7) ;

    // Calculate timestamps for CEST init and end day

    $initTime = strtotime("$initDay March $year");

    $endTime = strtotime("$initDay October $year");

    // Are we in summer time?

    if ($t > $initTime && $t < $endTime) {

        // We are in summer time, so add an hourto the timeStamp

        return ($t + 3600);

    } else {

        // We are NOT in summer time, so leave the Timestamp as is

        return ($t);

    }

}

?>