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    date_sunset

    (PHP 5, PHP 7, PHP 8)

    date_sunset — Returns time of sunset for a given day and location

    Warning

    This function has been DEPRECATED as of PHP 8.1.0. Relying on this function is highly discouraged. Use date_sun_info() instead.

    Description

    date_sunset(
        int $timestamp,
        int $returnFormat = SUNFUNCS_RET_STRING,
        ?float $latitude = null,
        ?float $longitude = null,
        ?float $zenith = null,
        ?float $utcOffset = null
    ): string|int|float|false

    date_sunset() returns the sunset time for a given day (specified as a timestamp) and location.

    Parameters

    timestamp

    The timestamp of the day from which the sunset time is taken.

    returnFormat

    returnFormat constants
    constant description example
    SUNFUNCS_RET_STRING returns the result as string 16:46
    SUNFUNCS_RET_DOUBLE returns the result as float 16.78243132
    SUNFUNCS_RET_TIMESTAMP returns the result as int (timestamp) 1095034606

    latitude

    Defaults to North, pass in a negative value for South. See also: date.default_latitude

    longitude

    Defaults to East, pass in a negative value for West. See also: date.default_longitude

    zenith

    zenith is the angle between the center of the sun and a line perpendicular to earth's surface. It defaults to date.sunset_zenith

    Common zenith angles
    Angle Description
    90°50' Sunset: the point where the sun becomes invisible.
    96° Civil twilight: conventionally used to signify the end of dusk.
    102° Nautical twilight: the point at which the horizon ends being visible at sea.
    108° Astronomical twilight: the point at which the sun ends being the source of any illumination.

    utcOffset

    Specified in hours. The utcOffset is ignored, if returnFormat is SUNFUNCS_RET_TIMESTAMP.

    Return Values

    Returns the sunset time in a specified returnFormat on success or false on failure. One potential reason for failure is that the sun does not set at all, which happens inside the polar circles for part of the year.

    Errors/Exceptions

    Every call to a date/time function will generate a E_WARNING if the time zone is not valid. See also date_default_timezone_set()

    Changelog

    Version Description
    8.1.0 This function has been deprecated in favor of date_sun_info().
    8.0.0 latitude, longitude, zenith and utcOffset are nullable now.

    Examples

    Example #1 date_sunset() example

    <?php

    /* calculate the sunset time for Lisbon, Portugal
    Latitude: 38.4 North
    Longitude: 9 West
    Zenith ~= 90
    offset: +1 GMT
    */

    echo date("D M d Y"). ', sunset time : ' .date_sunset(time(), SUNFUNCS_RET_STRING, 38.4, -9, 90, 1);

    ?>

    The above example will output something similar to:

    Mon Dec 20 2004, sunset time : 18:13

    Example #2 No sunset

    <?php
    $solstice     = strtotime('2017-12-21');
    var_dump(date_sunset($solstice, SUNFUNCS_RET_STRING, 69.245833, -53.537222));
    ?>

    The above example will output:

    bool(false)

    See Also

    • date_sun_info() - Returns an array with information about sunset/sunrise and twilight begin/end

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    User Contributed Notes 3 notes

    up
    1
    matt at mctsoft dot net
    5 years ago
    yes SUNFUNCS_RET_TIMESTAMP does return GMT(0) time

    so something like...

    $arr = localtime(date_sunset(time(),SUNFUNCS_RET_TIMESTAMP,51.5,0)); // London

    $hh = $arr[2];
    $mm = $arr[1];

    Will give figure out your localtime and daylight saving (BST)
    up
    -1
    nospam at nomail dot com
    6 years ago
    maybe I am wrong, but I think

    SUNFUNCS_RET_TIMESTAMP     return GMT(0) time

    SUNFUNCS_RET_STRING     Return local time
    SUNFUNCS_RET_DOUBLE     Return local time
    up
    -25
    michael at dayah dot com
    18 years ago
    I use an IP to location database to determine the visitor's approximate latitude and longitude and then serve them a day or night color scheme based on whether it is before civil dawn or dusk. I've had problems when not specifying the timezone, specifically a 1 hour error, so I use GMT.

    <?php
    date_default_timezone_set    ("GMT");

    function     scheme() {
                $sunrise = date_sunrise(time(), SUNFUNCS_RET_DOUBLE, $latitude, $longitude, 96, 0);
                $sunset = date_sunset(time(), SUNFUNCS_RET_DOUBLE, $latitude, $longitude, 96, 0);
                $now = date("H") + date("i") / 60 + date("s") / 3600;

            if (    $sunrise < $sunset)
                    if ((    $now > $sunrise) && ($now < $sunset)) return "day";
                    else return     "night";
            else
                    if ((    $now > $sunrise) || ($now < $sunset)) return "day";
                    else return     "night";
    }
    ?>
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