Don't forget that inside the arctic and antarctic circles the sun never sets/rises for part of the year so this function legitimately returns false!
(PHP 5, PHP 7)
date_sunrise — Returns time of sunrise for a given day and location
$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.sunrise_zenith")
[, float $gmt_offset = 0
]]]]] )
date_sunrise() returns the sunrise time for a given
day (specified as a timestamp) and location.
timestamp
The timestamp of the day from which the sunrise
time is taken.
format
| 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 |
latitudeDefaults to North, pass in a negative value for South. See also: date.default_latitude
longitudeDefaults to East, pass in a negative value for West. See also: date.default_longitude
zenithDefault: date.sunrise_zenith
gmtoffsetSpecified in hours.
Returns the sunrise time in a specified format on
success or FALSE on failure.
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()
| Version | Description |
|---|---|
| 5.1.0 |
Now issues the |
Example #1 date_sunrise() example
<?php
/* calculate the sunrise time for Lisbon, Portugal
Latitude: 38.4 North
Longitude: 9 West
Zenith ~= 90
offset: +1 GMT
*/
echo date("D M d Y"). ', sunrise time : ' .date_sunrise(time(), SUNFUNCS_RET_STRING, 38.4, -9, 90, 1);
?>
The above example will output something similar to:
Mon Dec 20 2004, sunrise time : 08:54
Don't forget that inside the arctic and antarctic circles the sun never sets/rises for part of the year so this function legitimately returns false!
The way to use this:
<?php
// De Bilt, The Netherlands, weather station #06260
$lat = 52.10; // North
$long = 5.18; // East
$offset = 1; // difference between GMT and local time in hours
$zenith=90+50/60;
echo "<br><p>Sunrise: ".date_sunrise(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
echo "<br>Sunset: ".date_sunset(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
$zenith=96;
echo "<br><p>Civilian Twilight start: ".date_sunrise(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
echo "<br>Civilian Twilight end: ".date_sunset(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
$zenith=102;
echo "<br><p>Nautical Twilight start: ".date_sunrise(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
echo "<br>Nautical Twilight end: ".date_sunset(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
$zenith=108;
echo "<br><p>Astronomical Twilight start: ".date_sunrise(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
echo "<br>Astronomical Twilight end: ".date_sunset(time(), SUNFUNCS_RET_STRING, $lat, $long, $zenith, $offset);
?>
Zenith according to the U.S. Navy's 1990 Almanac for Computers.
Thanks to George King.
More sources about this topic:
http://www.qarlos.free.fr/navegacion/Sextante/formulas.htm
http://williams.best.vwh.net/sunrise_sunset_algorithm.htm
http://www.kevinboone.com/suntimes.html
http://star-www.st-and.ac.uk/~fv/webnotes/chapt12.htm
Just for those that are as stupid as me
for the settings in php.ini and sunrise/sunset after googling for a while if found this info
;`Zenith' is the angle that the centre of the Sun makes to a line perpendicular to the Earth's surface.
;
; The best Overall figure for zenith is 90+(50/60) degrees for true sunrise/sunset
; Civil twilight 96 degrees - Conventionally used to signify twilight
; Nautical twilight 102 degrees - the point at which the horizon stops being visible at sea.
; Astronical twilight at 108 degrees - the point when Sun stops being a source of any illumination.
;
;date.sunrise_zenith = 90.583333 85.4
;date.sunset_zenith = 90.583333 85.4
If you are working in multiple timezones getting the offset from a date is a little tricky because you need it in hours.
<?php
$time = new DateTime('now', new DateTimeZone('America/Los_Angeles'));
date_sunrise(
$time->getTimestamp(),
SUNFUNCS_RET_TIMESTAMP,
38.4,
-9,
90,
$time->getOffset() / 3600
);
After some searching, I finally found a website that can calculate the sun's zenith. Just look up your city's lat/long (remember, west/south are negative even if it doesn't show where you look up the lat/long) and the time of sunrise/sunset and use this site:
http://solardat.uoregon.edu/cgi-bin/SolarPositionCalculator.cgi
You have to enter in the sunrise/sunset times separately, but it works.
San Diego is:
Lat: 32.73
Long: -117.17
Sunrise Z.: 90.7379
Sunset Z.: 90.8880