Predefined Constants

The DATE_* constants are defined and offer standard date representations, which can be used along with the date format functions (like date()).

Available returnFormat for date_sunrise() and date_sunset()
Warning

These constants are deprecated as of PHP 8.4.0. The corresponding date_sunrise() and date_sunset() functions are deprecated as of PHP 8.1.0.

SUNFUNCS_RET_TIMESTAMP (int)
Timestamp
SUNFUNCS_RET_STRING (int)
Hours:minutes (example: 08:02)
SUNFUNCS_RET_DOUBLE (int)
Hours as floating point number (example 8.75)
DATE_* constants
DATE_ATOM (string)
Atom (example: 2005-08-15T15:52:01+00:00); compatible with ISO-8601, RFC 3339, and XML Schema
HTTP Cookies (example: Monday, 15-Aug-2005 15:52:01 UTC)
DATE_ISO8601 (string)
ISO-8601-like (example: 2005-08-15T15:52:01+0000)

Note: This format is not compatible with ISO-8601, but is left this way for backward compatibility reasons. Use DATE_ISO8601_EXPANDED, DATE_ATOM for compatibility with ISO-8601 instead (ref ISO8601:2004 section 4.3.3 clause d).

DATE_ISO8601_EXPANDED (string)
ISO-8601 Expanded (example: +10191-07-26T08:59:52+01:00)

Note: This format allows for year ranges outside of ISO-8601's normal range of 0000-9999 by always including a sign character. It also ensures that the timezone part (+01:00) is compatible with ISO-8601.

DATE_RFC822 (string)
RFC 822 (example: Mon, 15 Aug 05 15:52:01 +0000)
DATE_RFC850 (string)
RFC 850 (example: Monday, 15-Aug-05 15:52:01 UTC)
DATE_RFC1036 (string)
RFC 1036 (example: Mon, 15 Aug 05 15:52:01 +0000)
DATE_RFC1123 (string)
RFC 1123 (example: Mon, 15 Aug 2005 15:52:01 +0000)
DATE_RFC7231 (string)
RFC 7231 (as of PHP 7.0.19 and 7.1.5) (example: Sat, 30 Apr 2016 17:52:13 GMT)
DATE_RFC2822 (string)
RFC 2822 (example: Mon, 15 Aug 2005 15:52:01 +0000)
DATE_RFC3339 (string)
Same as DATE_ATOM.
DATE_RFC3339_EXTENDED (string)
RFC 3339 EXTENDED format (example: 2005-08-15T15:52:01.000+00:00)
DATE_RSS (string)
RSS (example: Mon, 15 Aug 2005 15:52:01 +0000). Alias of DATE_RFC1123.
DATE_W3C (string)
World Wide Web Consortium (example: 2005-08-15T15:52:01+00:00). Alias of DATE_RFC3339.