时区偏移大于12小时意味着什么？

Question

MySQL仅从我的getOffset()函数的输出中扼杀了这八个时区。

时区偏移大于12小时意味着什么？您如何建议修改，以便$os保持在+/- 12小时之间？

function getOffset() {
    $os=(new \DateTime())->getOffset();
    return $os >= 0?'+'.gmdate("G:i", $os):'-'.gmdate("G:i", -$os);
}


foreach(DateTimeZone::listIdentifiers() as $tz) {
    date_default_timezone_set($tz);
    $os=getOffset();
    $hours=explode(':',$os)[0];
    if($hours>12 || $hours<-12) {
        echo("$tz has offset of $os.<br>");
    }
}

输出：

Antarctica/McMurdo has offset of +13:00.
Pacific/Apia has offset of +14:00.
Pacific/Auckland has offset of +13:00.
Pacific/Chatham has offset of +13:45.
Pacific/Enderbury has offset of +13:00.
Pacific/Fakaofo has offset of +13:00.
Pacific/Kiritimati has offset of +14:00.
Pacific/Tongatapu has offset of +13:00.