http://www.phally.com/other-things/2013/04/07/our-outdated-time-system

timesync.php

<?php

// Get solar minutes for seconds.
function solar($seconds) {
        $leap = 365.25 / 365;
        $inSeconds = $seconds * $leap;
        $inMinutes = $inSeconds / 60;
        return round($inMinutes);
}

// Get clock minutes for seconds.
function clock($seconds) {
        $inSeconds = $seconds;
        $inMinutes = $inSeconds / 60;
        return round($inMinutes);
}

// Get length of solar/clock sync.
function getSync() {
        $sec = 1;
        while (solar($sec) == clock($sec)) {
                $sec += 1;
        }
        return $sec;
}

$seconds = getSync();
$minutes = floor($seconds / 60);

echo "In sync for:" . PHP_EOL;
echo "- $seconds seconds" . PHP_EOL;
echo "- $minutes minutes" . PHP_EOL;

?>