diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 5dfbf58697..ba7ad34036 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -219,10 +219,12 @@ function wp_maybe_decline_date( $date ) {
 	 * translate this to 'on'. Do not translate into your own language.
 	 */
 	if ( 'on' === _x( 'off', 'decline months names: on or off' ) ) {
+
+		$months          = $wp_locale->month;
+		$months_genitive = $wp_locale->month_genitive;
+
 		// Match a format like 'j F Y' or 'j. F'
 		if ( @preg_match( '#^\d{1,2}\.? [^\d ]+#u', $date ) ) {
-			$months          = $wp_locale->month;
-			$months_genitive = $wp_locale->month_genitive;
 
 			foreach ( $months as $key => $month ) {
 				$months[ $key ] = '# ' . $month . '( |$)#u';
@@ -234,6 +236,19 @@ function wp_maybe_decline_date( $date ) {
 
 			$date = preg_replace( $months, $months_genitive, $date );
 		}
+
+		// Match a format like 'F jS' or 'F j' and change it to 'j F'
+		if ( @preg_match( '#^[^\d ]+ \d{1,2}(st|nd|rd|th)? #u', trim( $date ) ) ) {
+			foreach ( $months as $key => $month ) {
+				$months[ $key ] = '#' . $month . ' (\d{1,2})(st|nd|rd|th)?#u';
+			}
+
+			foreach ( $months_genitive as $key => $month ) {
+				$months_genitive[ $key ] = '$1 ' . $month;
+			}
+
+			$date = preg_replace( $months, $months_genitive, $date );
+		}
 	}
 
 	// Used for locale-specific rules
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 4f0a37560a..93f9e8b1f2 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45554';
+$wp_version = '5.3-alpha-45555';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.