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PHP date_sunset

PHP original manual for date_sunset [ show | php.net ]

date_sunset

(PHP 5, PHP 7)

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

Description

mixed date_sunset ( int $timestamp [, int $format = SUNFUNCS_RET_STRING [, float $latitude = ini_get("date.default_latitude") [, float $longitude = ini_get("date.default_longitude") [, float $zenith = ini_get("date.sunset_zenith") [, float $gmt_offset = 0 ]]]]] )

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.

format

format 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 integer (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.

gmtoffset

Specified in hours. The gmtoffset is ignored, if format is SUNFUNCS_RET_TIMESTAMP.

Errors/Exceptions

Every call to a date/time function will generate a E_NOTICE if the time zone is not valid, and/or a E_STRICT or E_WARNING message if using the system settings or the TZ environment variable. See also date_default_timezone_set()

Changelog

Version Description
5.1.0

Now issues the E_STRICT and E_NOTICE time zone errors.

Return Values

Returns the sunset time in a specified format 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.

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_sunrise() - Returns time of sunrise for a given day and location
  • date_sun_info() - Returns an array with information about sunset/sunrise and twilight begin/end