--- a/wp/wp-includes/class-wp-date-query.php	Fri Sep 05 18:40:08 2025 +0200
+++ b/wp/wp-includes/class-wp-date-query.php	Fri Sep 05 18:52:52 2025 +0200
@@ -317,7 +317,7 @@
 				$_year = $date_query['year'];
 			}
 
-			$max_days_of_year = gmdate( 'z', mktime( 0, 0, 0, 12, 31, $_year ) ) + 1;
+			$max_days_of_year = (int) gmdate( 'z', mktime( 0, 0, 0, 12, 31, $_year ) ) + 1;
 		} else {
 			// Otherwise we use the max of 366 (leap-year).
 			$max_days_of_year = 366;