以分钟为单位查找时区的午夜

虽然这个解决方案看起来有点丑，但它确实做到了我认为你想要的!本例使用-180分钟作为偏移量。

date_default_timezone_set('UTC');
// Work out which day the time zone is in
$day = strtotime('-180 minutes');
// Strip of the time part of the day, to give UTC midnight on the correct day
$utcMidnight = strtotime('midnight', $day);
// Now apply the offset in reverse to give the zone's midnight
$zoneMidnight = strtotime('+180 minutes', $utcMidnight);

您可以使用date_default_timezone_set使所有与时间相关的函数都承认偏移。首先要做的是将这些分钟转换成小时，因为UTC的n和n+1之间有1小时的差距。

$hours = $minutes / 60;

我还建议您先检查分钟值:

if($minutes % 60 == 0) // We're good.

现在，如果您想将UTC偏移量转换为时区，您可以创建以下函数:

<?php
function offsetToTimezone($offset){
    $timezones = array( 
        "-12" => "Pacific/Kwajalein", 
        "-11" => "Pacific/Samoa", 
        "-10" => "Pacific/Honolulu", 
        "-9" => "America/Juneau", 
        "-8" => "America/Los_Angeles", 
        "-7" => "America/Denver", 
        "-6" => "America/Mexico_City", 
        "-5" => "America/New_York", 
        "-4" => "America/Caracas", 
        "-3.5" => "America/St_Johns", 
        "-3" => "America/Argentina/Buenos_Aires", 
        "-2" => "Atlantic/Azores",
        "-1" => "Atlantic/Azores", 
        "0" => "Europe/London", 
        "1" => "Europe/Paris", 
        "2" => "Europe/Helsinki", 
        "3" => "Europe/Moscow", 
        "3.5" => "Asia/Tehran", 
        "4" => "Asia/Baku", 
        "4.5" => "Asia/Kabul", 
        "5" => "Asia/Karachi", 
        "5.5" => "Asia/Calcutta", 
        "6" => "Asia/Colombo", 
        "7" => "Asia/Bangkok", 
        "8" => "Asia/Singapore", 
        "9" => "Asia/Tokyo", 
        "9.5" => "Australia/Darwin", 
        "10" => "Pacific/Guam", 
        "11" => "Asia/Magadan", 
        "12" => "Asia/Kamchatka" 
    );
    return $timezones[$offset];
}
?>

…并使用它进行转换:

date_default_timezone_set(offsetToTimezone($hours));

顺便说一下，我建议你看看这个答案，它为你提供了一种更优雅的方式来实现offsetToTimezone的工作。

现在您的脚本已经配置在正确的时区，只需请求时间戳:

$timestamp = mktime(0, 0, 0);

如果在某些时候，你需要重置时区为默认，你可能需要date_default_timezone_get保存它:

$timezone = date_default_timezone_get();
// Change to another timezone based on your offset.
// Get your timestamp.
date_default_timezone_set($timezone);

我必须仔细考虑一下，但我认为这是我一直在寻找的解决方案。如果你认为这个算法不正确，请告诉我。

function getLastMidnightForOffset( $minuteOffset ) {
    $today = mktime( 0, 0, 0 );
    $tomorrow = $today + 86400;
    $yesterday = $today - 86400;
    $offset = $minuteOffset * 60;
    if ( time() + $offset >= $tomorrow ) {
        $localMidnight = $tomorrow - $offset;
    } elseif ( time() + $offset >= $today ) {
        $localMidnight = $today - $offset;
    } else {
        $localMidnight = $yesterday - $offset;
    }
    return $localMidnight;
}