date_sun_info

    (PHP 5 >= 5.1.2, PHP 7, PHP 8)

    date_sun_info — Returns an array with information about sunset/sunrise and twilight begin/end

    Description

    date_sun_info(int$timestamp, float$latitude, float$longitude): array

    Parameters

    timestamp

    Unix timestamp.

    latitude

    Latitude in degrees.

    longitude

    Longitude in degrees.

    Return Values

    Returns array on success or false on failure. The structure of the array is detailed in the following list:

    sunrise
    The timestamp of the sunrise (zenith angle = 90°35').
    sunset
    The timestamp of the sunset (zenith angle = 90°35').
    transit
    The timestamp when the sun is at its zenith, i.e. has reached its topmost point.
    civil_twilight_begin
    The start of the civil dawn (zenith angle = 96°). It ends at sunrise.
    civil_twilight_end
    The end of the civil dusk (zenith angle = 96°). It starts at sunset.
    nautical_twilight_begin
    The start of the nautical dawn (zenith angle = 102°). It ends at civil_twilight_begin.
    nautical_twilight_end
    The end of the nautical dusk (zenith angle = 102°). It starts at civil_twilight_end.
    astronomical_twilight_begin
    The start of the astronomical dawn (zenith angle = 108°). It ends at nautical_twilight_begin.
    astronomical_twilight_end
    The end of the astronomical dusk (zenith angle = 108°). It starts at nautical_twilight_end.

    The values of the array elements are either UNIX timestamps, false if the sun is below the respective zenith for the whole day, or true if the sun is above the respective zenith for the whole day.

    Changelog

    VersionDescription
    7.2.0 The calculation was fixed with regards to local midnight instead of local noon, which changes the results slightly.

    Examples

    Example #1 A date_sun_info() example

    <?php
    $sun_info     = date_sun_info(strtotime("2006-12-12"), 31.7667, 35.2333);
    foreach (    $sun_info as $key => $val) {
    echo     "$key: " . date("H:i:s", $val) . "\n";
    }
    ?>

    The above example will output:

    sunrise: 05:52:11 sunset: 15:41:21 transit: 10:46:46 civil_twilight_begin: 05:24:08 civil_twilight_end: 16:09:24 nautical_twilight_begin: 04:52:25 nautical_twilight_end: 16:41:06 astronomical_twilight_begin: 04:21:32 astronomical_twilight_end: 17:12:00

    Example #2 Polar night, with some processing

    <?php
    $tz     = new \DateTimeZone('America/Anchorage');

    $si = date_sun_info(strtotime("2022-12-21"), 70.21, -148.51);
    foreach (    $si as $key => $value) {
    echo
    match (    $value) {
    true => 'always',
    false => 'never',
    default =>     date_create("@{$value}")->setTimeZone($tz)->format( 'H:i:s T' ),
    },
    ": {$key}",
    "\n";
    }
    ?>

    The above example will output:

    never: sunrise never: sunset 12:52:18 AKST: transit 10:53:19 AKST: civil_twilight_begin 14:51:17 AKST: civil_twilight_end 09:01:47 AKST: nautical_twilight_begin 16:42:48 AKST: nautical_twilight_end 07:40:47 AKST: astronomical_twilight_begin 18:03:49 AKST: astronomical_twilight_end

    Example #3 Midnight sun (Tromsø, Norway)

    <?php
    $si     = date_sun_info(strtotime("2022-06-26"), 69.68, 18.94);
    print_r($si);
    ?>

    The above example will output:

    Array ( [sunrise] => 1 [sunset] => 1 [transit] => 1656240426 [civil_twilight_begin] => 1 [civil_twilight_end] => 1 [nautical_twilight_begin] => 1 [nautical_twilight_end] => 1 [astronomical_twilight_begin] => 1 [astronomical_twilight_end] => 1 )

    Example #4 Calculating length of day (Kyiv)

    <?php
    $si     = date_sun_info(strtotime('2022-08-26'), 50.45, 30.52);
    $diff = $si['sunset'] - $si['sunrise'];
    echo     "Length of day: ",
    floor($diff / 3600), "h ",
    floor(($diff % 3600) / 60), "s\n";
    ?>

    The above example will output:

    Length of day: 13h 56s
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