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<title>Returns time of sunset for a given day and location</title>
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<div class="refnamediv">
<h1 class="refname">date_sunset</h1>
<p class="verinfo">(PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">date_sunset</span> — <span class="dc-title">
Returns time of sunset for a given day and location
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.date-sunset-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><strong>date_sunset</strong></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$timestamp</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$format</code><span class="initializer"> = SUNFUNCS_RET_STRING</span></span>
[, <span class="methodparam"><span class="type">float</span> <code class="parameter">$latitude</code><span class="initializer"> = ini_get("date.default_latitude")</span></span>
[, <span class="methodparam"><span class="type">float</span> <code class="parameter">$longitude</code><span class="initializer"> = ini_get("date.default_longitude")</span></span>
[, <span class="methodparam"><span class="type">float</span> <code class="parameter">$zenith</code><span class="initializer"> = ini_get("date.sunset_zenith")</span></span>
[, <span class="methodparam"><span class="type">float</span> <code class="parameter">$gmt_offset</code><span class="initializer"> = 0</span></span>
]]]]] )</div>
<p class="para rdfs-comment">
<span class="function"><strong>date_sunset()</strong></span> returns the sunset time for a given
day (specified as a <code class="parameter">timestamp</code>) and location.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.date-sunset-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">timestamp</code></dt>
<dd>
<p class="para">
The <code class="parameter">timestamp</code> of the day from which the sunset
time is taken.
</p>
</dd>
<dt>
<code class="parameter">format</code></dt>
<dd>
<p class="para">
<table class="doctable table">
<caption><strong><code class="parameter">format</code> constants</strong></caption>
<thead>
<tr>
<th>constant</th>
<th>description</th>
<th>example</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>SUNFUNCS_RET_STRING</td>
<td>returns the result as <span class="type"><a href="language.types.string.html" class="type string">string</a></span></td>
<td>16:46</td>
</tr>
<tr>
<td>SUNFUNCS_RET_DOUBLE</td>
<td>returns the result as <span class="type"><a href="language.types.float.html" class="type float">float</a></span></td>
<td>16.78243132</td>
</tr>
<tr>
<td>SUNFUNCS_RET_TIMESTAMP</td>
<td>returns the result as <span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span> (timestamp)</td>
<td>1095034606</td>
</tr>
</tbody>
</table>
</p>
</dd>
<dt>
<code class="parameter">latitude</code></dt>
<dd>
<p class="para">
Defaults to North, pass in a negative value for South.
See also: <a href="datetime.configuration.html#ini.date.default-latitude" class="link">date.default_latitude</a>
</p>
</dd>
<dt>
<code class="parameter">longitude</code></dt>
<dd>
<p class="para">
Defaults to East, pass in a negative value for West.
See also: <a href="datetime.configuration.html#ini.date.default-longitude" class="link">date.default_longitude</a>
</p>
</dd>
<dt>
<code class="parameter">zenith</code></dt>
<dd>
<p class="para">
<code class="parameter">zenith</code> is the angle between the center of the sun
and a line perpendicular to earth's surface. It defaults to
<a href="datetime.configuration.html#ini.date.sunset-zenith" class="link">date.sunset_zenith</a>
<table class="doctable table">
<caption><strong>Common <code class="parameter">zenith</code> angles</strong></caption>
<thead>
<tr>
<th>Angle</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>90°50'</td>
<td>Sunset: the point where the sun becomes invisible.</td>
</tr>
<tr>
<td>96°</td>
<td>Civil twilight: conventionally used to signify the end of dusk.</td>
</tr>
<tr>
<td>102°</td>
<td>Nautical twilight: the point at which the horizon ends being visible at sea.</td>
</tr>
<tr>
<td>108°</td>
<td>Astronomical twilight: the point at which the sun ends being the source of any illumination.</td>
</tr>
</tbody>
</table>
</p>
</dd>
<dt>
<code class="parameter">gmtoffset</code></dt>
<dd>
<p class="para">
Specified in hours.
The <code class="parameter">gmtoffset</code> is ignored, if
<code class="parameter">format</code> is
<strong><code>SUNFUNCS_RET_TIMESTAMP</code></strong>.
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 errors" id="refsect1-function.date-sunset-errors">
<h3 class="title">Errors/Exceptions</h3>
<p class="para">
Every call to a date/time function will generate a <strong><code>E_NOTICE</code></strong>
if the time zone is not valid, and/or a <strong><code>E_STRICT</code></strong>
or <strong><code>E_WARNING</code></strong> message
if using the system settings or the <var class="varname"><var class="varname">TZ</var></var> environment
variable. See also <span class="function"><a href="function.date-default-timezone-set.html" class="function">date_default_timezone_set()</a></span></p>
</div>
<div class="refsect1 changelog" id="refsect1-function.date-sunset-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr><td>5.1.0</td><td><p class="para">
Now issues the <strong><code>E_STRICT</code></strong> and <strong><code>E_NOTICE</code></strong>
time zone errors.</p></td></tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.date-sunset-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the sunset time in a specified <code class="parameter">format</code> on
success or <strong><code>FALSE</code></strong> 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.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.date-sunset-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-2799">
<p><strong>Example #1 <span class="function"><strong>date_sunset()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #FF8000">/* calculate the sunset time for Lisbon, Portugal<br />Latitude: 38.4 North<br />Longitude: 9 West<br />Zenith ~= 90<br />offset: +1 GMT<br />*/<br /><br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">date</span><span style="color: #007700">(</span><span style="color: #DD0000">"D M d Y"</span><span style="color: #007700">). </span><span style="color: #DD0000">', sunset time : ' </span><span style="color: #007700">.</span><span style="color: #0000BB">date_sunset</span><span style="color: #007700">(</span><span style="color: #0000BB">time</span><span style="color: #007700">(), </span><span style="color: #0000BB">SUNFUNCS_RET_STRING</span><span style="color: #007700">, </span><span style="color: #0000BB">38.4</span><span style="color: #007700">, -</span><span style="color: #0000BB">9</span><span style="color: #007700">, </span><span style="color: #0000BB">90</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output
something similar to:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Mon Dec 20 2004, sunset time : 18:13
</pre></div>
</div>
</div>
<div class="example" id="example-2800">
<p><strong>Example #2 No sunset</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$solstice </span><span style="color: #007700">= </span><span style="color: #0000BB">strtotime</span><span style="color: #007700">(</span><span style="color: #DD0000">'2017-12-21'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">date_sunset</span><span style="color: #007700">(</span><span style="color: #0000BB">$solstice</span><span style="color: #007700">, </span><span style="color: #0000BB">SUNFUNCS_RET_STRING</span><span style="color: #007700">, </span><span style="color: #0000BB">69.245833</span><span style="color: #007700">, -</span><span style="color: #0000BB">53.537222</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
bool(false)
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.date-sunset-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.date-sunrise.html" class="function" rel="rdfs-seeAlso">date_sunrise()</a> - Returns time of sunrise for a given day and location</span></li>
<li class="member"><span class="function"><a href="function.date-sun-info.html" class="function" rel="rdfs-seeAlso">date_sun_info()</a> - Returns an array with information about sunset/sunrise and twilight begin/end</span></li>
</ul>
</p>
</div>
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