WordPress RSS date time

Overview

RSS (Really Simple Syndication) feeds require properly formatted date-time values to comply with the RSS 2.0 specification. WordPress provides built-in functions to convert MySQL datetime values stored in the database into RFC 2822 compliant formats required by RSS readers and aggregators.

RSS Date Requirements

The RSS 2.0 specification mandates that all date-time values conform to RFC 822 (updated by RFC 2822). This format ensures compatibility across feed readers, podcatchers, and news aggregators worldwide.

RFC 2822 Date Format:

Example: Thu, 21 Dec 2023 16:01:07 +0200

Last Build Date

The first example shows how to format the last build date of an RSS feed using the post's creation date in RFC 2822 format (required by RSS specification).

1<lastBuildDate>
2    <?php echo mysql2date(' r', $post->post_date, false); ?>
3</lastBuildDate>

The <lastBuildDate> element indicates when the channel content last changed. Feed readers use this to determine if they need to refresh their cached content.

Publication Date

The second example demonstrates formatting individual post publication dates with a specific timezone offset (+0300) and custom date format for RSS pubDate elements.

1<pubDate>
2    <?php echo mysql2date( 'D, d M Y H:i:s +0300',
3    get_post_time( 'Y-m-d H:i:s', true ), false ); ?>
4</pubDate>

The <pubDate> element specifies when the item was published. This is critical for feed readers to sort items chronologically and identify new content.

Key Functions Reference

mysql2date()

Converts a MySQL datetime string to a specified PHP date format.

Function Signature:

1mysql2date( string $format, string $date, bool $translate = true ): string|int|false

Parameters:

Return Value: Formatted date string, Unix timestamp (if format is 'G' or 'U'), or false on failure.

get_post_time()

Retrieves the time at which the post was written.

Function Signature:

1get_post_time( string $format = 'U', bool $gmt = false, int|WP_Post $post = null, bool $translate = false ): string|int|false

Parameters:

PHP Date Format Characters

Timezone Offset Formats

The timezone offset in RSS dates must be expressed as +HHMM or -HHMM:

Additional Code Examples

Dynamic Timezone from WordPress Settings

Retrieve the timezone offset from WordPress settings instead of hardcoding:

1<pubDate>
2    <?php
3    $gmt_offset = get_option('gmt_offset');
4    $timezone = sprintf('%+03d00', $gmt_offset);
5    echo mysql2date('D, d M Y H:i:s ' . $timezone,
6        get_post_time('Y-m-d H:i:s', true), false);
7    ?>
8</pubDate>

Using WordPress Timezone String

For sites configured with named timezones (e.g., "Europe/Moscow"):

1<pubDate>
2    <?php
3    $timezone_string = get_option('timezone_string');
4    if ($timezone_string) {
5        $datetime = new DateTime(get_post_time('Y-m-d H:i:s', true), new DateTimeZone('UTC'));
6        $datetime->setTimezone(new DateTimeZone($timezone_string));
7        echo $datetime->format('D, d M Y H:i:s O');
8    } else {
9        echo mysql2date('r', get_post_time('Y-m-d H:i:s', true), false);
10    }
11    ?>
12</pubDate>

Modified Date for Updated Posts

Include the last modified date for posts that have been updated after initial publication:

1<?php if (get_the_modified_time('U') > get_post_time('U')) : ?>
2<atom:updated xmlns:atom="http://www.w3.org/2005/Atom">
3    <?php echo mysql2date('c', get_the_modified_time('Y-m-d H:i:s', true), false); ?>
4</atom:updated>
5<?php endif; ?>

Common Issues and Solutions

Incorrect Timezone Display

Problem: Dates show wrong timezone offset.

Solution: Ensure WordPress timezone settings are configured correctly in Settings → General → Timezone. Use get_option('gmt_offset') or get_option('timezone_string') for dynamic timezone handling.

Date Translation Issues

Problem: Day and month names appear in localized language instead of English.

Solution: Set the third parameter of mysql2date() to false to disable translation. RSS feeds require English date names per specification.

MySQL Date Format Mismatch

Problem: mysql2date() returns false or unexpected results.

Solution: Verify the input date follows MySQL format YYYY-MM-DD HH:MM:SS. WordPress stores dates in this format in the post_date and post_date_gmt columns.

Related WordPress Functions