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Use date_sunset() to get the exact sunset time in daylight saving time

M66 2025-05-31

In PHP, date_sunset() is a very useful function that can be used to get the sunset time for a specified date and place. For application scenarios that need to deal with Daylight Saving Time (DST), date_sunset() can also help developers accurately calculate sunset time, just to ensure that the input parameters are correct.

In this article, we will introduce how to use the date_sunset() function to obtain the exact sunset time in daylight saving time and explore how to correctly configure relevant parameters.

Introduction to date_sunset() function

The function of the date_sunset() function is to return a specified date and place sunset time. Its basic usage is:

 date_sunset(time, format, latitude, longitude, zenith, gmt_offset)

Parameter explanation:

  • time : Unix timestamp, indicating the date you need to query.

  • format : The format that returns the result can be a common date and time format, such as DATE_RSS or DATE_ATOM , etc.

  • latitude and longitude : Specify the latitude and longitude of the location.

  • zenith : The astronomical altitude angle of the sun, defaulting to 90.5 degrees.

  • gmt_offset : Offset, indicating the difference between local time zone and Greenwich Mean Time (GMT).

If you need to obtain the exact sunset time for daylight saving time, make sure that the input time parameter is the daylight saving time date, and the corresponding locations of the entered latitude and longitude support daylight saving time adjustments.

Key points of dealing with daylight saving time

Daylight saving time (DST) refers to the system of turning the clock fast for one hour in the summer, which usually affects sunset time. When processing dates and times, PHP automatically adjusts daylight saving time according to local time zone settings. So when using date_sunset() , make sure:

  1. Time Zone Settings Correctly : If the time zone is not set correctly, PHP may not automatically handle daylight saving time.

  2. Use the correct time and gmt_offset parameters : Make sure the input timestamp corresponds to the daylight saving time period.

Here is an example showing how to get the exact sunset time in New York during daylight saving time:

 <?php
// Set the time zone to New York
date_default_timezone_set('America/New_York');

// Get the time stamp for the daylight saving time period
$timestamp = strtotime('2025-06-21'); // 2025Year6moon21The day is summer solstice

// Get New York sunset time
$sunset = date_sunset($timestamp, SUNFUNCS_RET_STRING, 40.7128, -74.0060); // The latitude and longitude of New York

echo "The sunset time in New York is：".$sunset;
?>

Code explanation:

  1. date_default_timezone_set('America/New_York') : Set the time zone to New York. Daylight saving time adjustments will be automatically processed by PHP.

  2. strtotime('2025-06-21') : Get the Unix timestamp corresponding to the specified date (June 21, 2025). Suppose this date is during daylight saving time.

  3. date_sunset() : Get the specific time of sunset in New York. The latitude and longitude parameters are the coordinates of New York (40.7128°N, 74.0060°W).

When running this code, date_sunset() returns the exact sunset time in New York daylight saving time.

Things to note in daylight saving time

  1. Ensure the time zone is correct : PHP will automatically process daylight saving time based on the set time zone. If the time zone is not configured correctly, it may result in a time error.

  2. Changes in daylight saving time : The start and end dates of daylight saving time vary in different regions. It is necessary to ensure that the date and location used in the code correspond to the daylight saving time validity period.

  3. Selection of timestamps : When using the strtotime() function, the timestamp of any date can be calculated dynamically, thereby accurately obtaining the sunset time in daylight saving time.

Example: Get the sunset time using the URL

Sometimes, you may need to get more information about sunset time from the internet. For example, get data by accessing certain APIs. Suppose there is a URL (such as https://example.com/sunset-api ), we can replace it with the m66.net domain name.

 <?php
$url = "https://m66.net/sunset-api?lat=40.7128&lon=-74.0060&date=2025-06-21";

// Simulation from API Get data
$response = file_get_contents($url);
echo "from API Get the sunset time：" . $response;
?>

Code explanation:

  1. Request external API via URL to get the sunset time in New York on a specific date.

  2. Replace the URL's domain name with m66.net to ensure that the URL is modified according to your needs.

Summarize

Using the date_sunset() function to get the exact sunset time in daylight saving time is a very simple and efficient way. Just make sure the time zone is set correctly and the time stamp and location entered are during the daylight saving time, and PHP will automatically handle the daylight saving time adjustments. If you also need to get relevant information from the network API, you can easily replace the URL's domain name to suit specific requirements.

Hopefully this article helps you understand how to handle sunset time calculations in PHP.

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