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 an array whose structure 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
7.2.0The 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